(2412,101,'7.1.1 Instantaneous Overcurrent Relays for Radial Feeder Protection','','single','html','<p style=\"text-align:justify\"><span style=\"font-size:14px\">In this case all relays R<sub>1</sub>, R<sub>2</sub> and R<sub>3</sub> are instantaneous overcurrent relays. Fault current is inversely proportional to impedance up to fault point.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">i.e.,&nbsp;<span class=\"math-tex\">\\(I_f =\\frac{E}{Z}\\)</span>&nbsp;&nbsp;Where, E = Induced emf of the generator.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">This is the formula for finding fault current for a three-phase fault. As the impedance of transmission line is proportional to line length, fault current is inversely proportional to distance between a relaying point and a fault point. Hence relay R<sub>1</sub> is set to reach up to bus B, R<sub>2</sub> to reach up to bus C and so on.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">i.e., Pick-up setting of relay R<sub>1</sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(= \\frac{I_f\\hspace{0.2cm}at\\hspace{0.2cm}B}{CT_1\\hspace{0.2cm}ratio}\\)</span></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Where I<sub>f</sub> at B = Fault current for three-phase fault at bus B And CT<sub>1 </sub>ratio = CT ratio of CT<sub>1</sub>.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Similar is the formula for pick-up setting of relays R<sub>2</sub> and R<sub>3</sub>. Thus, R<sub>1</sub> will not operate for fault in section II of radial feeder. Similarly, R<sub>2</sub> will protect for faults only in line segment BC (section II). In this way, the discrimination for faults in different zones (or sections) is achieved. This method of discrimination suffers from many disadvantages as follows:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<ol>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Unrealistic setting accuracy requirement: Protective relays are not supposed to be very accurate. The tolerance in pick-up value of <u><span class=\"math-tex\">\\(\\pm\\)</span></u>&nbsp;5%&nbsp;(or as bad as&nbsp;<u><span class=\"math-tex\">\\(\\pm\\)</span></u>10%&nbsp;so often) is allowed by standards. This means that relay R<sub>1</sub> (and hence R<sub>2</sub> and R<sub>3</sub> also) will either not reach up to bus B or will reach beyond bus B. None of these can be permitted in protection practice. As, if R<sub>1</sub> underreaches, some portion of line will be unprotected and if it overreaches, it is unwanted operation for faults in another zone (or section).</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">This method does not provide remote back-up protection, which is a major disadvantage.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Let us first define new terms.</span></p>\n	</li>\n</ol>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16251397341625139734.jpg\" style=\"height:485px; width:800px\" /></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">Z<sub>s</sub> = Source Impedance = Impedance from source to relaying point. (Refer figure 7.3).</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">Z<sub>l</sub> = Line Impedance = Impedance from relaying point to fault.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">For R<sub>1</sub>, the reach is up to bus B, therefore, Z<sub>l</sub> = Z<sub>AB</sub>.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">It can be appreciated that Z<sub>s</sub> for relays R<sub>2</sub> and R<sub>3</sub> are different and not equal to that for R<sub>1.</sub></span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">It is obvious that, Fault current,&nbsp;<span class=\"math-tex\">\\(I_f=\\frac{E}{Z_s+Z_l}\\)</span>&nbsp;.&nbsp;Now if&nbsp;<span class=\"math-tex\">\\(Z_s&gt;&gt;Z_l\\)</span>,&nbsp;<span class=\"math-tex\">\\(I_f=\\frac{E}{Z_s}\\)</span>,&nbsp;and fault current is not proportional to line length. It is approximately constant for fault at any location of line. In this case, discrimination between faults in different sections (or zones) is not possible. Instantaneous overcurrent relays are affected the most by Z<sub>s</sub>/Z<sub>l</sub> ratio and are of no use for high Z<sub>s</sub>/Z<sub>l</sub> ratio.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<ol start=\"4\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">The relaying system using instantaneous overcurrent relays does not exploit short-time fault current withstand capability of the equipment to be protected as instantaneous overcurrent relays operate within 1-3 cycles.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">It also does not take into account the transient stability limit of the machines. As such, the generators can feed the fault current for some time (known as critical clearing time which may be few cycles or a fraction of a second) without loosing synchronism as decided by equal area criterion. The transient fault may vanish within this time.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Instantaneous overcurrent relays suffer from the problem of transient overreach, because of which there can be an unwanted operation of the relay for faults external to its assigned zone.</span></p>\n	</li>\n</ol>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">We have discussed earlier that the fault current is asymmetric with reference to time axis following the instant of fault inception. The fault current may be asymmetric or may not be so depending on instant of voltage waveshape at which fault occurs, as already discussed. Hence, the relays are always set for symmetrical rms value of fault current. When asymmetry is present in fault current, current measured by relay is higher (2.8 times the rms value if the relay operates within time equal to zero) than the symmetrical rms fault current. The d. c. offset component of fault current decays exponentially but this decay takes 15-30 cycles depending upon L/R ratio of the power system being protected. The instantaneous overcurrent relay operates within 1-3 cycles and therefore it measures a current which is higher than symmetric rms value. In other words, the relay sees the fault nearer than the location where it is located. Thus, the relay overreaches. This overreach is transient as there will be no overreach after 15-30 cycles. Hence time-delay relays do not suffer from this disadvantage.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">For this reason, the instantaneous overcurrent relay has to be set for the three-phase &nbsp;fault current with maximum generation (all generators are in operation) at 80 % of line section to be protected, assuming transient overreach of the relay as 20 %. However, in this case, remnant 20 % will be unprotected. Hence, instantaneous overcurrent relays alone cannot be used for radial feeder protection, but they are used in conjunction with time-delayed relays so that 80 % of line section can be protected instantaneously and remnant 20 % section protected by time-delayed unit of a protective relay.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">The formula for deciding setting of instantaneous high-set unit is as follows:</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">Setting of H. S. Inst.&nbsp;<span class=\"math-tex\">\\(Unit=\\frac{100B}{100-A}\\)</span>&nbsp;</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">Where A = % overreach of instantaneous overcurrent relay.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">&nbsp;B = Magnitude of three-phase symmetric RMS fault&nbsp;Current at the end of feeder section (in CT secondary&nbsp;Amp)</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16260061041626006104.jpg\" style=\"height:386px; width:800px\" /></span></p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">For example, refer to figure 7.2 and data as follows:</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">CT ratio of CT<sub>1</sub> = 500/1 amp, Fault current for three-phase fault at bus B with maximum generation is 5000 amp, % overreach of instantaneous overcurrent relay R<sub>1</sub> = 10 %.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">Hence, <span class=\"math-tex\">\\(B=\\frac{5000}{500}\\)</span></span></p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;=&nbsp; 10 amp.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">Therefore, setting of H. S. Inst. <span class=\"math-tex\">\\(Unit=\\frac{100\\times 10}{100-10}\\)</span>&nbsp;=11.11 amp or 1111%&nbsp;of 1 amp. With setting range 400-2000 % in steps of 50 %, setting selected is 1150 % (or 1200 % if steps are of 100 %).</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">With the advent of static and numerical relays, this problem of transient overreach is solved to certain extent. We have seen that,</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(i=I_m[sin(\\omega t+\\theta-\\phi)\\)</span></span></p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp;&nbsp;<span class=\"math-tex\">\\(+sin(\\phi-\\theta)e^{\\frac{-Rt}{L}}]\\)</span></span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">This asymmetry is present in fault current waveshape, but if this fault current is differentiated before feeding to a protective relay, the d. c. offset will be attenuated.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\frac{di}{dt}=I_m[\\omega\\hspace{0.1cm}cos(\\omega t+\\theta-\\phi))\\)</span></span></p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp;<span class=\"math-tex\">\\(-\\frac{R}{L}sin(\\phi-\\theta)e^{\\frac{-Rt}{L}}]\\)</span></span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">This means that d. c. offset is attenuated to R/L times (as L&gt;&gt;R in power systems) the original value of d. c. offset. Cosine wave is sinusoidal only, so it does not change steady-state component but for phase-shift which overcurrent relay does not measure (in other words, overcurrent relay is not affected by this phase-shift). If R/L is 0.1, d. c. offset is attenuated to 10 %. This means that the relay which has % overreach of 10 % will now overreach by only 1 %. Double differentiation will make the relay practically immune to the problem of transient overreach.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">Differentiation of current can be realized in static relays by using op-amp as a differentiator. In numerical relays it is yet faster because it takes samples every millisecond (a typical sampling interval is one millisecond).</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\frac{di}{dt}=\\frac{i_2-i_1}{\\Delta t}\\)</span>&nbsp;,</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">Where i<sub>1</sub> = First Sample,</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">i</span><sub>2</sub><span style=\"font-size:14px\"> = Second Sample,</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\Delta t\\)</span>&nbsp;=&nbsp;Sampling Interval</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<ol start=\"7\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Type of Fault: It is known that the magnitude of fault current for three-phase fault (L-L-L) is more than that for double line fault (L-L). Different relays (Earth-fault or Ground relays) will operate for L-g and L-L-g faults and these relays require a separate treatment which we will be discussing later in this module.</span></p>\n	</li>\n</ol>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;<span class=\"math-tex\">\\(I_{LLL}=\\frac{E}{Z_1}\\)</span>&nbsp;and&nbsp;</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;<span class=\"math-tex\">\\(I_{LL}=\\frac{\\sqrt3 E}{Z_1+Z_2}\\)</span>&nbsp;</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;&nbsp;<span class=\"math-tex\">\\(=\\frac{\\sqrt3E}{2Z_1}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Therefore,</span></p>\n\n<p style=\"text-align:justify\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;<span style=\"font-size:14px\"><span class=\"math-tex\">\\(I_{LL}=0.866I_{LLL}\\)</span></span></p>\n\n<p>&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">Now, if relay R<sub>1</sub> is made to reach up to bus B for double line fault, it will overreach for triple line fault and if it is set to reach up to bus B for triple line fault, it will underreach for double line fault. This statement is true for relays R<sub>2</sub> and R<sub>3</sub> also for similar faults at bus C and D respectively.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">Because of these problems involved with the use of instantaneous overcurrent relays, such relays alone are not used for transmission line protection. However, they are used in conjunction with time-delayed relays having in-built high-set inst. unit to trip the line instantaneously for faults in the vicinity of relay location (usually 80 % of line section).</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>','','1','7.1.1',NULL,'1','2','1','0','1','2021-08-18 09:03:55','2021-08-18 14:33:55'),(2413,101,'7.1.2 Definite Time Overcurrent Relays for Radial Feeder Protection','','single','html','<p style=\"text-align:justify\"><span style=\"font-size:14px\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16251391421625139142.jpg\" style=\"height:489px; width:800px\" /></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Instead of using magnitude of fault current as a discriminating quantity for discriminating location of faults in different zones, time of operation of relays is used as a discriminating quantity for the same purpose. This solves all the problems discussed in foregoing section. For this purpose, relays R<sub>1</sub>, R<sub>2</sub> and R<sub>3</sub> of figure 7.2 are definite time overcurrent relays. The distance-time characteristic of such relays is shown in figure 7.4. The maximum pick-up current of relay R<sub>1</sub> is such that it reaches up to bus C for double line fault at bus C with minimum generation. This means that if the relay R<sub>1</sub> reaches beyond bus C, it is not objectionable but if it does not reach up to bus C, relay R<sub>1</sub> will not provide 100 % back-up to relay R<sub>2</sub>. Similarly, R<sub>2</sub> should reach up to bus D and R<sub>3</sub> should cover longest 415 V distributor emanating from bus D. The time setting for relay R<sub>3</sub> is t<sub>3</sub> sec (say 0.1 second). R<sub>3</sub> has to be coordinated with fuse so that for a fault in 415 V distributor, fuse melts and trips the distributor. Should the fuse fail to trip the distributor, R<sub>3</sub> will offer back-up protection. If there is a fault in line section CD, relay R<sub>3</sub> will operate and trip the breaker CB<sub>3</sub> at the end of time delay t<sub>3</sub> sec. Should any of the component of switchgear (CT, CB<sub>3</sub> or R<sub>3</sub>) fail, relay R<sub>2</sub> will give back-up protection. This is known as remote back-up. Obviously, time of operation of relay R<sub>2</sub> is set at t<sub>2</sub> sec (say 0.35 sec) i. e., more than time of operation of relay R<sub>3</sub>. The difference (t<sub>2</sub>-t<sub>3</sub>) is t<sub>d</sub>, the discrimination time margin. The reason for this discrimination time as 0.25 sec will be discussed later. Similarly, R<sub>1</sub> is set to operate after time delay t<sub>1</sub> sec (say 0.6 sec). There can be such 4 or 5 (or more) sections in series. In this case, the time of operation of a relay near power source is objectionably high. This is dangerous as the fault currents for faults in the vicinity of source are very large. Thus, the contradiction of the scheme of protection is that the heaviest fault is cleared the slowest. This difficulty can be overcome by introducing an instantaneous high-set unit in-built with definite time unit such that the faults (L-L-L fault) up to 80 % of line section from relaying point are cleared instantaneously. By the inclusion of such high-set instantaneous units, the saving in time of clearing the faults as shown by shaded portion in figure 7.4 is achieved. The faults beyond 80 % of line section are taken care of by time delayed unit.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">As instantaneous overcurrent relays are highly prone to Z<sub>s</sub>/Z<sub>l</sub> ratio, if Z<sub>l</sub> is too small (line is too short), Z<sub>s</sub>/Z<sub>l</sub> will be high. </span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Therefore,</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(I_f=\\frac{E}{Z_s+Z_l}\\)</span>&nbsp;</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp;<span class=\"math-tex\">\\(\\cong\\frac{E}{Z_s}\\)</span></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">The instantaneous overcurrent relay cannot be that accurate as it can differentiate between fault immediately after relaying point in first line section and fault 10 (or 20) km away in the next line section. This can happen for very short transmission line just emanating from source. For example, a 220 kV transmission line from Ukai hydro power plant to Ukai thermal power plant is just 6 km long. In such a case, high-set instantaneous unit cannot be provided or if provided, it has to be blocked which results in very dangerously long time of operation of relay R<sub>1</sub> (in figure 7.4). Hence definite time overcurrent relays also do not find its application for radial feeder protection.</span></p>','','1','7.1.2',NULL,'1','2','1','0','1','2021-08-19 13:20:37','2021-08-19 18:50:37'),(2414,101,'7.1.3 Normal Inverse IDMT Overcurrent Relays for Radial Feeder Protection','','single','html','<p style=\"text-align:justify\"><span style=\"font-size:14px\">It is seen that farther the fault from the source, less is the magnitude of fault current, hence more time can be allowed (and must be allowed as fault can be transient) to clear the fault. The equipment of power system can withstand small fault currents for longer time. On the other hand, if the fault is nearer to the source, fault current magnitude will be high and hence such fault should be cleared quickly. Therefore, the relays, the time of operation of which is inversely proportion to fault current magnitude, are the best to be applied to radial feeder protection.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16252230511625223051.jpg\" style=\"height:489px; width:800px\" /></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Therefore, the relays R<sub>1</sub>, R<sub>2</sub> and R<sub>3</sub> of figure 7.2 are inverse time (IDMT) overcurrent relays. The distance-time characteristic using such relays is shown in figure7.5. It can be appreciated that the selectivity is yet maintained with lower time of operation for faults near relaying point. Back-up protection is also offered. Reader shall also appreciate the speed of operation of inverse time overcurrent relays vis-&agrave;-vis the definite time equivalents as indicated by shaded area in figure 7.5. The high-set instantaneous unit can be in-built with inverse time unit in this case as well as shown in figure 7.5.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><br />\n&nbsp;</p>','','1','7.1.3',NULL,'1','2','1','0','1','2021-07-02 16:21:45','2021-07-02 16:21:45'),(2415,101,'7.1.4 Rules for Setting the IDMT Overcurrent Relays','','single','html','<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\"><strong>Phase Relays:</strong></span></p>\n	</li>\n</ul>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">The phase relays are meant for sensing triple line or double line faults (i.e., faults not involving ground).</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\"><strong><u>Plug-Settings:</u></strong></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\"><strong>Plug-settings are decided considering the following rules:</strong></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<ol>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">The plug-setting must not be less than the maximum load current including permissible continuous overload unless monitored by an undervoltage relay or unless voltage-controlled overcurrent relay is used.</span></p>\n	</li>\n</ol>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16252256391625225639.jpg\" style=\"height:375px; width:800px\" /></span></p>\n\n<p>&nbsp;</p>\n\n<ol start=\"2\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">While estimating plug-setting, an allowance must be made of the fact that the pick-up of an IDMT overcurrent relay varies from 1.05 to 1.3 times the plug-setting as per standards. Consider figure 7.6 to understand this rule. Current flowing in the radial feeder of figure 7.6 is 400 amp (maximum load current). Hence, plug-settings of relays R<sub>1</sub>, R<sub>2</sub> and R<sub>3</sub> are set at 100 % according to rule 1 above. Now, due to overload or fault somewhere in 415 V distributor emanating from bus D, 550 amp current is passing through radial feeder. With reference to allowable limits in pick-up, it is quite possible that pick-up of relay R<sub>3</sub> is 650 amp (1.3 times P. S. of R<sub>3</sub>) and pick-up current of relay R<sub>2</sub> is 525 amp (1.05 times P. S. of R<sub>2</sub>). This means that relay R<sub>2</sub> will pick-up and R<sub>3</sub> will not at all start. However, time of operation of R<sub>2</sub> is set to be more than that of relay R<sub>3</sub>, R<sub>2</sub> will operate and R<sub>3</sub> will not operate in this case. This is against the requirement of selectivity of protective relaying system. Hence, if selectivity is to be maintained,</span></p>\n	</li>\n</ol>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">Pick-up of R<sub>2</sub> &gt; Pick-up of R<sub>3</sub></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">or,&nbsp;<sub><span class=\"math-tex\">\\(1.05\\times P.S.of\\hspace{0.1cm}R_2&gt;1.3\\times P.S.of\\hspace{0.1cm}R_3\\)</span></sub></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\)</span>&nbsp;&nbsp;<span class=\"math-tex\">\\(P.S.of\\hspace{0.1cm}R_2&gt;\\frac{1.3}{1.05}\\times P.S.of\\hspace{0.1cm}R_3\\)</span></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">In figure 7.6, P. S. of </span></p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">&nbsp;<span class=\"math-tex\">\\(R_2&gt;\\frac{1.3}{1.05}\\times 500\\hspace{0.1cm}amp\\)</span></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp;<span class=\"math-tex\">\\(&gt;619\\hspace{0.1cm}amp\\)</span></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp;<span class=\"math-tex\">\\(&gt;123.8%\\)</span>&nbsp;&nbsp;of 500 amp (CT primary rating of relaying point R<sub>2</sub>).</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">Hence, 125 % shall be set. Similarly, P. S. of R<sub>1</sub> is set at 175 %, based on same consideration. </span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">i.e., P. S. of &nbsp;<span class=\"math-tex\">\\(R_1&gt;\\frac{1.3}{1.05}\\times P.S. of \\hspace{0.1cm}R_2.\\)</span></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16252256881625225688.jpg\" style=\"height:489px; width:800px\" /></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<ol start=\"3\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">The relay shall reach at least up to the end of next protected zone. In figure 7.5, relay R<sub>1</sub> shall reach for an L-L fault at bus C with minimum generation (and relay R<sub>2</sub> shall reach up to bus D with same conditions). This is required to ensure back-up protection.</span></p>\n	</li>\n</ol>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">It is obvious that the higher of the two plug-settings offered by rule 1 and rule 2 shall be considered for setting. This value of plug-setting must satisfy rule 3. If this is not satisfied, one has to use voltage-controlled overcurrent relay to satisfy rule 3.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong><u>Time Setting:</u></strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong><u><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16252257151625225715.jpg\" style=\"height:727px; width:800px\" /></u></strong></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Relay R<sub>3</sub> of figure 7.5 has to be coordinated with fuse (or MCCB) characteristic. The TMS of R<sub>3</sub> will be decided based on this grading. TMS of R<sub>2</sub> has to be chosen for the highest fault current that concerns relay R<sub>2</sub> and R<sub>3</sub>. This fault current is a triple line fault immediately after relaying point R<sub>3</sub> with maximum generation (this fault location will be at bus C as circuit breaker of relaying point R<sub>3</sub> is usually just 10 to 20 meters far from bus C). The value of this fault current is I<sub>f</sub> as shown in figure 7.7. The time-current characteristics of relays R<sub>2</sub> and R<sub>3</sub> are also shown in the figure 7.7. Obviously, R<sub>2</sub> should operate later than relay R<sub>3</sub> but discrimination time margin &ldquo;af&rdquo; shall be as small as possible as speed of operation is also a requirement of protective relaying system.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Referring to figure 7.7,</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">oa = Standard time of operation of relay R<sub>3</sub> = 0.23 sec.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">This assumes fault current equal to 20&nbsp;&times; P.S.&nbsp;of relay and TMS = 0.1.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">The relay may not operate at the end of this time exactly as certain time errors are allowed by standards. As per standards, following time tolerances are allowed:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:123px; width:900px\">\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:178px\">\n			<div style=\"text-align:center\"><strong><span style=\"font-size:28px\">PSM</span></strong></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:172px\">\n			<div style=\"text-align:center\"><strong><span style=\"font-size:28px\">Time Tolerance</span></strong></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:178px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Up to 2</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:172px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Not Defined.</span></div>\n\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Relay shall operate</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:178px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2-4</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:172px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\"><span class=\"math-tex\">\\(\\pm12.5\\)</span>&nbsp;%</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:178px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4-20</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:172px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\"><span class=\"math-tex\">\\(\\pm7.5\\)</span>&nbsp;%</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p>&nbsp;</p>\n\n<p>&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Therefore, ab = - 7.5 % error in operating time of relay R<sub>3</sub> = 0.017 sec.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">The relay R<sub>3</sub> has, hence, operated at the expiry of time ob. Relay, then, gives signal to circuit breaker. CB takes certain time to clear the fault. Good SF<sub>6</sub> circuit breakers take 2 cycles to clear the fault (contact separation, arcing and final arc quenching).</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Therefore, bc = Breaker time = 2 cycles = 0.04 sec.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">At the end of time oc, the fault is cleared and current flowing through the relay is zero. But the relay R<sub>2</sub> also had sensed the fault and had started. It should reset, but due to mechanical inertia in electromagnetic relays and electrical inertia (due to inductance of relay circuitry, current reduces to zero exponentially) in static/numerical relays, it keeps on counting time for a little time (after clearance of the fault) known as overshoot or overtravel. This is de.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">de = 5 cycles in electromagnetic relays</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; = 1 cycle in static/numerical relays</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; = 0.02 sec.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">ef = + 7.5 % &nbsp;time error of the relay R<sub>2</sub>.</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp;&nbsp;&nbsp;&nbsp; = 0.036 sec.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">It is very obvious that points c and d shall not coincide or overlap.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">cd = safety margin = 0.1 sec.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Hence for all practical purposes, we will use a fixed discrimination time margin of 0.25 sec between time of operations of two successive relays.</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>','','1','7.1.4',NULL,'1','2','1','0','1','2021-07-13 05:17:19','2021-07-13 10:47:19'),(2416,101,'7.1.5 Application Example','','single','html','<p style=\"text-align:justify\">?</p>\n\n<p>?</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong><u>&nbsp;Example 1:</u></strong> </span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16252334201625233420.jpg\" style=\"height:679px; width:900px\" /></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.8 shows a single line diagram of a portion of power system network. The relays R<sub>1</sub> to R<sub>7</sub> are normal inverse IDMT relays. The maximum power flowing in transmission lines is tabulated in table 7.1 below:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:37px; width:900px\">\n	<caption>\n	<p><span style=\"font-size:20px\"><strong>Table 7.1: Maximum loads in Different Lines</strong></span></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:263px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Power flowing in 220 kV line AB</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:115px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">197 MW at </span></div>\n\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.8 pf lag</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:263px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Power flowing in 132 kV line CD</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:115px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">66 MW at</span></div>\n\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.8 pf lag</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:263px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Power flowing in 66 kV line</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:115px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">22 MW at</span></div>\n\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.8 pf lag</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">This power is calculated considering 10 % overload on lines. The fault currents at different buses are tabulated in table 7.2 below:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:94px; width:900px\">\n	<caption>\n	<p><span style=\"font-size:20px\"><strong>Table 7.2: Fault Currents at Different Buses</strong></span></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:106px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:149px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for L-L-L fault in amp</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:161px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for L-L fault in amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:106px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:149px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">5750</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:161px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4980</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:106px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:149px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3017</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:161px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2613</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:106px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:149px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3240</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:161px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2806</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:106px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">D</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:149px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2146</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:161px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1858</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:106px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">E</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:149px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2880</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:161px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2494</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p>&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">TMS of R<sub>7</sub> is set at 0.1. Calculate plug-settings and time settings of phase relays R<sub>1</sub> to R<sub>7</sub>. Also calculate setting of high-set instantaneous unit in-built with relay R<sub>1</sub> given that % overreach of H. S. unit is 10 %.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong><u>Solution:</u></strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong><u>Plug-Settings:</u></strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">P. S. of R<sub>7</sub> is based on rated full load power of 66 kV transmission line.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p><span style=\"font-size:14px\">Full load current through 66 kV line </span></p>\n\n<p><span style=\"font-size:14px\"><span class=\"math-tex\">\\(=\\frac{22\\times10^3}{\\sqrt 3\\times66\\times0.8}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><em>= 240.56 amp.</em></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\)</span>&nbsp;<span class=\"math-tex\">\\(P.S.\\hspace{0.1cm}of\\hspace{0.1cm}R_7\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(= \\frac{240.56\\times100}{300}\\)</span>&nbsp;</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">= 80.18%,hence plug-setting of R<sub>7&nbsp;</sub>is to be set at 100%.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">P. S. of R<sub>6</sub> will be dependent on maximum power transferred through 132 kV line.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Maximum current that can pass through secondary of 100 MVA transformer is equal to</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(=\\frac{66\\times10^3}{\\sqrt3\\times66\\times0.8}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">=721.68 amp.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\)</span>&nbsp;P.S. of R<sub>6&nbsp;</sub>=&nbsp;<span class=\"math-tex\">\\(\\frac{72168\\times100}{1000}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;= 72.16 %.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Therefore, plug-setting of R<sub>6</sub> shall be 75 %.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Let us check-up coordination between relays R<sub>6&shy;</sub> and R<sub>7</sub>,</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">P.S. of R<sub>6&nbsp;</sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(&gt;\\frac{1.3}{1.05}\\times\\)</span>&nbsp;P. S. of R<sub>7</sub> in CT primary amp.</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&gt; 371.43 amp</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(&gt;\\frac{371.43\\times100}{1000}\\)</span>&nbsp;or 37.14 % of CT primary rating of CT at relaying point R<sub>6</sub></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Hence our selection 75 % is correct.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">similarly,P.S. of R<sub>5&nbsp;</sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(= \\frac{721.68\\times66\\times100}{132\\times500}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp;= 72.168%</span></p>\n\n<p>&nbsp;</p>\n\n<p><span style=\"font-size:14px\">And P. S. of R<sub>5</sub></span></p>\n\n<p><span style=\"font-size:14px\"><span class=\"math-tex\">\\(&gt;\\frac{1.3\\times P.S.\\hspace{0.1cm}of\\hspace{0.1cm}R_6\\times66}{1.05\\times132}\\)</span></span></p>\n\n<p><span style=\"font-size:14px\"><span class=\"math-tex\">\\(=\\frac{1.3\\times0.75\\times1000\\times 66}{1.05\\times132}\\)</span></span></p>\n\n<p><span style=\"font-size:14px\">&nbsp;=464.28 amp.</span></p>\n\n<p>&nbsp;</p>\n\n<p><span style=\"font-size:14px\">Hence, P. S. of R<sub>5</sub>&nbsp;</span></p>\n\n<p><span style=\"font-size:14px\"><span class=\"math-tex\">\\(&gt;\\frac{464.28\\times 100}{500}\\)</span>&nbsp;% of CT rating.</span></p>\n\n<p><span style=\"font-size:14px\">&gt; 92.85 %, hence next higher available setting of R<sub>5</sub> as 100 % is selected.</span></p>\n\n<p>&nbsp;</p>\n\n<p><span style=\"font-size:14px\">On the same line of calculations </span></p>\n\n<p><span style=\"font-size:14px\">(&nbsp;<span class=\"math-tex\">\\(\\frac{1.3}{1.05}\\)</span>&nbsp;grading principle), P. S. of R<sub>4</sub> is to be set at 125 %.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">P. S. of R<sub>3</sub> will depend on maximum power transmitted through 220 kV line.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">P.S. of R<sub>3&nbsp;</sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(=\\frac{197\\times10^3\\times100}{\\sqrt3\\times132\\times0.8\\times1500}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><sub>&nbsp;</sub>= 71.80 % of CT rating.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">For proper coordination,</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">P.S. of R<sub>3</sub>&nbsp;<span class=\"math-tex\">\\(&gt; \\frac{1.3}{1.05}\\times\\)</span>&nbsp;P. S. of R<sub>4</sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;<span class=\"math-tex\">\\(&gt;\\frac{1.3}{1.05}\\times1.25\\times500\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><sub>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </sub>&nbsp;&gt;&nbsp;51.58 % of CT rating. Hence selection of 75 % as P. S. of R3 is correct.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">P.S. of R<sub>2&nbsp;</sub><span class=\"math-tex\">\\(&gt; \\frac{1.3\\times P.S.\\hspace{0.1cm}of\\hspace{0.1cm}R_3\\times132}{1.05\\times220}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;<span class=\"math-tex\">\\(&gt;\\frac{1.3\\times0.75\\times1500\\times132\\times100}{1.05\\times220\\times1000}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&gt; 83.57 %, hence P. S. of R<sub>2</sub> shall be set at 100 %.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">On the same line of calculation, P. S. of R<sub>1</sub> shall be set at 125 %.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong><u>Time Settings:</u></strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong><u>R<sub>6</sub>-R<sub>7</sub> coordination:</u></strong> The worst (maximum) fault current is 2880 amp.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">PSM of R<sub>7&nbsp;</sub><span class=\"math-tex\">\\(=\\frac{2880}{300}\\)</span>&nbsp;= 9.6.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\)</span>&nbsp;&nbsp;Top Time of operation of R<sub>7</sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><em><sub>&nbsp;</sub></em><span class=\"math-tex\">\\(=\\frac{3}{log_{10}9.6}\\times0.1=0.3054\\)</span>&nbsp;sec.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\)</span>&nbsp;Top of R<sub>6 </sub>= 0.3054 + 0.25 =0.5554 sec.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">PSM of R<sub>6&nbsp;</sub>=&nbsp;<span class=\"math-tex\">\\(\\frac{2880}{0.75\\times 1000}\\)</span>&nbsp;= 3.84.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Now,&nbsp;<span class=\"math-tex\">\\(\\frac{3}{log_{10}3.84}\\times TMS\\hspace{0.1cm}of\\hspace{0.1cm}R_6\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp;= 0.5554</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\)</span>&nbsp; TMS of R<sub>6</sub>=0.108.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Hence TMS of R<sub>6</sub> shall be set at 0.15.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>R<sub>5</sub>-R<sub>6</sub> coordination:</strong> The maximum fault current = 2880 amp.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">PSM of R<sub>6</sub> = 3.84, Top of R<sub>6</sub> = 0.77 sec.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Therefore, Top of R<sub>5</sub> = 1.02 sec.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">PSM of R<sub>5&nbsp;</sub><span class=\"math-tex\">\\(=\\frac{2880\\times66}{500\\times132}\\)</span>&nbsp;</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;= 2.88</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\)</span>&nbsp; TMS of R<sub>5&nbsp;</sub><span class=\"math-tex\">\\(=\\frac{1.02\\times log_{10}2.88}{3}\\)</span><sub>&nbsp;</sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><sub>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;</sub> &nbsp;= 0.156.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Hence TMS of R<sub>5</sub> shall be set at 0.2.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><u><strong>R<sub>4</sub>-R<sub>5</sub> coordination:</strong> </u>Fault current =2146 amp.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">PSM of R<sub>5</sub> = 4.292. Top of R<sub>5</sub> = 0.9483 sec. Therefore, Top of R<sub>4</sub> =1.198 sec.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">PSM of R<sub>4</sub> = 3.43</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\)</span>&nbsp;&nbsp;TMS of R<sub>4&nbsp;</sub><span class=\"math-tex\">\\(=\\frac{1.198\\times log_{10}3.43}{3}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; = 0.213.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Hence TMS of R<sub>4</sub> = 0.25 selected.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">On the same line of calculations,</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">TMS of R<sub>3</sub> = 0.2</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">TMS of R<sub>2</sub> = 0.15</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">TMS of R<sub>1</sub> = 0.2</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Setting of H. S. unit of relay R<sub>1</sub>:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">setting&nbsp;<span class=\"math-tex\">\\(=\\frac{100B}{100-A}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;<span class=\"math-tex\">\\(=\\frac{100\\times\\frac{3017}{1000}}{90}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><em>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; </em>= 3.35 amp=335 % of 1 amp.&nbsp;</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">But minimum available setting is 400 %, hence 400 % shall be set.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Let us summarize the final relay settings in table 7.3 below:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:94px; width:900px\">\n	<caption>\n	<p><span style=\"font-size:20px\"><strong>Table 7.3: Summary of Relay Settings of Example 1</strong></span></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:106px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Relay</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:121px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Plug-Setting in % of Relay Rating</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:113px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">TMS</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:106px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>1</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:121px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">125</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:113px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.2</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:106px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>2</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:121px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">100</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:113px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.15</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:106px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>3</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:121px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">75</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:113px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.2</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:106px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>4</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:121px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">125</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:113px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.25</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:106px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>5</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:121px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">100</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:113px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.2</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:106px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>6</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:121px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">75</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:113px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.15</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:106px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>7</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:121px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">100</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:113px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.1</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p>&nbsp;</p>\n\n<p>&nbsp;</p>\n\n<p>?</p>\n\n<p>?</p>','','1','7.1.5',NULL,'1','2','1','0','1','2021-08-18 09:13:15','2021-08-18 14:43:15'),(2417,101,'7.1.6 Problems in Application of Normal Inverse IDMT Overcurrent Relays','','single','html','<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Z<sub>s</sub>/Z<sub>l</sub> Ratio: As already discussed,</span></p>\n	</li>\n</ul>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(I_f=\\frac{E}{Z_s+Z_l}\\)</span>&nbsp;.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16253776981625377698.jpg\" style=\"height:366px; width:900px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16266936771626693677.jpg\" style=\"height:960px; width:800px\" /></p>\n\n<p style=\"text-align:justify\"><strong><span style=\"font-size:20px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Fig.7.10: Better Discriminetion Using Very Inverse and Extremly Characteristics</span></strong></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">If Z<sub>s&nbsp;</sub>&gt;&gt; Z<sub>l&nbsp;</sub>(which occurs in end-zone feeders as shown in figure 7.9), the difference between fault current magnitude for a fault at F<sub>1</sub> (immediately after relaying point R<sub>3</sub>) and that for a fault at F<sub>2</sub> (at the end of feeder section as shown in figure) is insignificant. Hence there will be no significant difference in time of operation of relay R<sub>3</sub> for both these fault locations. Hence, the normal inverse overcurrent characteristic is not justified where&nbsp;Z<sub>s</sub>/Z<sub>l&nbsp;</sub><span class=\"math-tex\">\\(\\geq\\)</span>&nbsp;2. The remedy is to use a very inverse characteristic. Referring to figure 7.10, for the same difference in fault current magnitudes (PSM = 3&nbsp;and PSM = 5), the difference in time of operation of normal inverse overcurrent relay is 2 sec, that of very inverse overcurrent relay is 3.4 sec&nbsp; and that of extremely inverse overcurrent relay is 6.67 sec. This clearly shows that very inverse overcurrent relay provides better discrimination than normal inverse overcurrent relay and extremely inverse overcurrent relay is the best in this respect. Another useful advantage is closer matching of extremely inverse overcurrent relay with MCCB characteristic. Therefore, lower time of operation of relay R<sub>3</sub> can be achieved. Hence, consequently lower TMS of R<sub>2</sub> and R<sub>1</sub> too can be set. The selectivity is yet maintained.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">The second problem is the varying generating capacities to match with the load variations. No doubt, when the load is less at night, one cannot switch off the thermal power plant as starting time of this plant is about 7 hours from fully cool condition. But hydro power plant, gas turbine plant or diesel power plant can be switched off fast and can be quickly switched ON also when desired. At night, when the load is less, small number of generators are connected in the power system and hence the magnitude of fault current will be less. In the limiting case, the fault current with minimum generation (least number of generators connected in the system) may be less than the load current with maximum generation (maximum number of generators connected). However, the fault current is less than the CMR of equipment, it is harmful because:</span></p>\n\n	<ol>\n		<li style=\"list-style-type:none\">\n		<ol style=\"list-style-type:lower-roman\">\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">The voltage has dropped (practically zero) at fault point.</span></p>\n			</li>\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">The flow of NPS (negative phase sequence) currents, in case of unsymmetrical faults give rise to double frequency eddy current flow in iron of the rotor of all machines overheating the rotor [heat produced due to X amp of NPS current is approximately 6 times that produced by same amount of positive sequence current (I<sup>2</sup>Rt)]. Hence negative sequence current of smaller magnitude than positive sequence current can prove to be more harmful.</span></p>\n			</li>\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">The flow of zero sequence current (which is third harmonic current) gives rise to eddy current losses (in machines and transformers) which are 9 times (proportional to f<sup>2</sup>) that due to positive sequence currents. Thus, again, lower magnitude of fault current containing negative and zero sequence components is harmful.</span></p>\n			</li>\n		</ol>\n		</li>\n	</ol>\n	</li>\n</ul>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16253777671625377767.jpg\" style=\"height:567px; width:900px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16253777971625377797.jpg\" style=\"height:367px; width:900px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">As I<sub>Lmax&nbsp;</sub>&gt;&nbsp;I<sub>fmin</sub>, it is difficult to set a simple IDMT overcurrent relay. Instead, voltage-controlled overcurrent relay can be used and relay is set for I<sub>Lmax</sub>. When fault occurs, voltage collapses below 70 % of V<sub>R</sub> (rated voltage) and plug-setting reduces to 40 % of set value. If voltage-controlled relay is not available, an undervoltage relay can be used in conjunction with simple overcurrent relay. Overcurrent relay is set for I<sub>fmin</sub> and undervoltage relay for 70 % V<sub>R</sub>.&nbsp;Referring to figure 7.11(a), and 7.11(b), when the normal load current is flowing during the time of day, as I<sub>L</sub> &gt;&nbsp;I<sub>f</sub>, relay 51 will operate closing 51-1 [figure 7.11(b)]. But as voltage is normal, undervoltage relay 27 is energized opening 27-1. Hence, 86 is not triggered and no tripping of breaker as required. If fault occurs at night, 51 operates and 27 deenergizes (as voltage is less than 70 % of V<sub>R</sub>) closing both 51-1 and 27-1. 86 gets energized, 86-1 closes, 52-a is already closed, hence 52-TC is energized tripping breaker as required.</span></p>','','1','7.1.6',NULL,'1','2','1','0','1','2021-08-19 13:23:00','2021-08-19 18:53:00'),(2418,101,'7.1.7 Rules for Setting IDMT Ground Relays','','single','html','<p style=\"text-align:justify\"><span style=\"font-size:14px\">The ground relays are meant for sensing ground faults i.e., L-g and L-L-g faults. Following are the considerations while setting ground relays.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<ol style=\"list-style-type:lower-alpha\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">A ground relay shall not operate for L-L-L or L-L fault, because, if it operates, it will be difficult for line maintenance staff to find the sustained fault while patrolling the line. It is one of the important functions of the protective relaying system to indicate the type of fault.</span></p>\n	</li>\n</ol>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16261742071626174207.jpg\" style=\"height:555px; width:800px\" /></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16261742481626174248.jpg\" style=\"height:428px; width:800px\" /></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">A ground relay is connected in residual circuit of three line CTs as shown in figure 7.12. It can be very easily understood that the current flowing through a ground relay under normal operating conditions is zero (as vector sum of I<sub>R</sub>, I<sub>Y</sub> and I<sub>B</sub> is zero). Therefore, the plug-setting of a ground relay is not dependent on normal load current unlike phase relays. In case of L-L-L-g fault also, as I<sub>Rf</sub> + I<sub>Yf</sub> + I<sub>Bf</sub> = 0 (because L-L-L-g fault is a symmetrical fault), no current will pass through the ground relay. Therefore, ground relay does not operate for this fault. As such, ground relay should not operate for phase faults (L-L-L-g, L-L-L or L-L). The ground relay will not operate for L-L faults also. For Y-B fault, I<sub>Y</sub> = -I<sub>B</sub> and I<sub>R</sub> = 0 (pre-fault currents are assumed to be zero) which gives, I<sub>R</sub> + I<sub>Y</sub> + I<sub>B</sub> = 0. Hence, no current will flow through ground relay. Only zero sequence current can pass through ground relay which is a case for either L-g fault or L-L-g fault. Hence ground relay or earth-fault relay will operate for L-g faults and L-L-g faults only. The plug-setting (or sensitivity) of a ground relay is dependent on possible mismatch between three line CTs. In case of L-L-L-g fault, fault current will be very large (may be 10, 15 or 20 times the CMR of equipment or transmission line). The CTs may saturate because of this large current and magnetizing (saturation) characteristic of three line CTs may not be identical [as shown in figure 7.12(a)]. This would give rise to a spill current flowing through a ground relay causing unwanted operation (as ground relay should not operate for phase faults). Therefore, the plug-setting of a ground relay must be higher than this spill current due to mismatch of saturation characteristics of three line CTs.</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16261742881626174288.jpg\" style=\"height:616px; width:800px\" /></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16261743261626174326.jpg\" style=\"height:727px; width:800px\" /></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">If higher sensitivity of a ground relay is required, the ground relay can be connected in different ways as shown in figure 7.13(a) and 7.13(b). For connections as shown in figure 7.13(a), neutral point should be available on the terminal block of equipment (transformer). It is obvious that the current will flow through neutral circuit in case of L-g and L-L-g faults only. For connections as shown in figure 7.13(b), CBCT (Core Balance CT) is required and CBCT can be used in case of cables only and not in case of overhead lines. The clearance between R, Y and B phases for overhead lines is large and use of CBCT will require core of large diameter and there will be problems of leakage flux. Therefore, application of CBCT is restricted usually for 6.6 kV and 11 kV indoor switchgears.</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">Monitoring the ground relay by an undervoltage unit is usually not required or volage-controlled ground overcurrent relay is generally not used because zero sequence impedance of the system is very large. Also, zero sequence network is terminated at the nearest grounded transformer. The zero-sequence current varies with distance to fault and is not affected by variation in generating conditions.</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<ol start=\"2\" style=\"list-style-type:lower-alpha\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">If L-g fault occurs very far from relaying point [some 100 km (or more) away in transmission line), the fault current magnitude will be very small.</span></p>\n	</li>\n</ol>\n\n<p style=\"text-align:justify\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;<span style=\"font-size:14px\"><span class=\"math-tex\">\\(I_{Lg}=\\frac{E}{Z_1+Z_2+Z_0+3Z_n+3Z_f}\\)</span>, </span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Where Z<sub>1</sub> = Positive Sequence Impedance.</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Z<sub>2</sub> = Negative Sequence Impedance.</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Z<sub>0</sub> = Zero Sequence Impedance.</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp;Z<sub>n</sub> = Deliberate Impedance Connected in the Neutral Circuit.</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Z<sub>f</sub> = Fault Resistance.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">For transmission line, Z<sub>1</sub> = Z<sub>2</sub> and for E. H. V. lines, Z<sub>0</sub> is approximately 4 times Z<sub>1</sub>. Even if we assume Z<sub>n</sub> to be zero, Z<sub>f</sub> is quite large as,</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">Z<sub>f</sub> = R<sub>f</sub> = Resistance of flash-over path + Resistance of iron tower + Tower footing Resistance.</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">In case of asphalt surfaces (hilly areas), the tower footing resistance (or soil resistivity) would be quite large resulting in Z<sub>f</sub> equal to 20 ohms (or in worst case even 50 ohms). Thus, fault current magnitude can be even less than normal full load current. Hence, the setting range of ground relays is available as 5-20 %, 10-40 % and 20-80 % of relay rating (in seven equal steps).</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16261743801626174380.jpg\" style=\"height:494px; width:800px\" /></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<ol start=\"3\" style=\"list-style-type:lower-alpha\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">If there is a delta-wye transformer between two successive relays (usually in power system, the delta-wye transformers are there between two successive relays as voltage is required to be generally stepped down to meet with economic voltage of transmission unless the substation is just a switching substation), a ground fault on star connected secondary is not reflected on delta connected primary side. L-g fault on star connected secondary side will be seen as L-L fault on primary side. Hence, ground relay on primary side cannot sense the fault (refer figure 7.14). Two successive relays are, then, independent and need not be coordinated. The demerit, because of this fact is that the relay on source side will not give back-up to a relay on load side. A ground relay connected across neutral CT as shown in figure 7.13(a) will give back-up to a ground relay connected in residual circuit of three line CTs.</span></p>\n	</li>\n</ol>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16292788101629278810.jpg\" style=\"height:489px; width:800px\" /></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">Because of this fact, referring to figure 7.5,</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(P.S.of\\hspace{0.2cm} ground\\hspace{0.2cm} relay\\hspace{0.2cm} R_2 \\)</span></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(&gt;\\frac{1.3}{1.05}\\times P.S. of\\hspace{0.2cm}ground\\hspace{0.2cm}relay\\hspace{0.2cm}R_3\\)</span></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">only if there is no delta-wye transformer intervening between relays R<sub>2</sub> and R<sub>3</sub>. Also ground relay R<sub>2</sub> is to be made to reach up to bus D only if there is no delta-wye transformer between relay R<sub>2</sub> and bus D. Relay R<sub>2</sub> can be set independent of relay R<sub>3</sub> and TMS of R<sub>2</sub> can be less than that of R<sub>3</sub>. Relay R<sub>2</sub> can be set to operate even instantaneously if need be. All these arguments hold for coordination between relays R<sub>1</sub> and R<sub>2</sub> also.</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">As delta-wye transformer is usually there between two successive relays, the requirements to satisfy rule 2 and 3 of phase relays do not hold good for ground relays. Moreover, for time setting, the time of operation of R<sub>2</sub> = time of operation of R<sub>3</sub> + 0.25, only if there is no transformer intervening between relays R<sub>2</sub> and R<sub>3</sub>.</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<ol start=\"4\" style=\"list-style-type:lower-alpha\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">The fourth consideration is with reference to excitation current of CTs. While calculating plug-setting, we were referring all calculations in terms of CT primary. This means that if plug-setting of a relay is 100 % (of 1 amp), it is 1 amp. If the relay is connected across secondary of 100/1 amp CT, the plug-setting is 100 amp in primary terms. But this statement is not fully correct as 100 amp in primary is not transformed as 1 amp. Because of excitation current (let us assume a realistic value of 0.05 amp) of CT, 100 amp is transformed as 0.95 (1.0 &ndash; 0.05) amp. Therefore, when we say 100 % plug-setting means 100 amp in primary, there is an error of approximately 5 %. In this case, 100 % mean 105 amp in primary and not 100 amp. This error was ignored in all earlier calculations as the error is quite small.</span></p>\n	</li>\n</ol>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">With ground relays this error is quite large. If there is an L-g fault, the current in secondary of CT due to this fault will have to feed excitation current requirement of all the three line CTs plus the current juice for operation of a ground relay. For 100/1 CT, if 25 amp is the magnitude of fault current for L-g fault, it will be reflected as 0.25 amp out of which 0.15 (3 times 0.05) amp will be required to excite the cores of the CTs and remnant 0.1 amp (which means 10 % of 1 amp) will flow through the ground relay. Thus, if 10 % is the plug setting of a ground relay, it means 25 amp in primary of a CT (which means 25 % of 100 amp rating). The effect of excitation current of CTs on sensitivity of a ground relay is demonstrated in table 7.4 below:</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:47px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.4: Effect of Excitation Current of CTs on Sensitivity of a Ground Relay</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:59px\">\n			<div style=\"text-align:center\"><strong><span style=\"font-size:28px\">P. S. of Ground Relay</span></strong></div>\n\n			<div style=\"text-align:center\"><strong><span style=\"font-size:28px\">%</span></strong></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:82px\">\n			<div style=\"text-align:center\"><strong><span style=\"font-size:28px\">P. S. of Ground Relay in Amp </span></strong></div>\n\n			<div style=\"text-align:center\"><strong><span style=\"font-size:28px\">CT sec = 1 Amp</span></strong></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:80px\">\n			<div style=\"text-align:center\"><strong><span style=\"font-size:28px\">3 I<sub>e</sub> =</span></strong></div>\n\n			<div style=\"text-align:center\"><strong><span style=\"font-size:28px\">3 &times;&nbsp;0.05 = 0.15 Amp</span></strong></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:85px\">\n			<div style=\"text-align:center\"><strong><span style=\"font-size:28px\">CT Secondary Current in Amp</span></strong></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:83px\">\n			<div style=\"text-align:center\"><strong><span style=\"font-size:28px\">CT Primary Current (100/1 CT)</span></strong></div>\n\n			<div style=\"text-align:center\"><strong><span style=\"font-size:28px\">Amp</span></strong></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:84px\">\n			<div style=\"text-align:center\"><strong><span style=\"font-size:28px\">Sensitivity of a Relay in CT Primary Terms</span></strong></div>\n\n			<div style=\"text-align:center\"><strong><span style=\"font-size:28px\">%</span></strong></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:81px\">\n			<div style=\"text-align:center\"><strong><span style=\"font-size:28px\">% Error</span></strong></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:59px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Q</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:82px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">X</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:80px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Y</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:85px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">X + Y</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:83px\">\n			<div style=\"text-align:center\">&nbsp;</div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:84px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">P</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:81px\">\n			<div>&nbsp;</div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:59px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">5</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:82px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.05</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:80px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.15</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:85px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.2</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:83px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">20</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:84px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">20</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:81px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">300</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:59px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">10</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:82px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.10</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:80px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.15</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:85px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.25</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:83px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">25</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:84px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">25</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:81px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">150</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:59px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">20</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:82px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.2</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:80px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.15</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:85px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.35</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:83px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">35</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:84px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">35</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:81px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">75</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:59px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">40</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:82px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.4</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:80px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.15</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:85px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.55</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:83px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">55</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:84px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">55</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:81px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">37.5</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:59px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">80</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:82px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.8</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:80px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.15</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:85px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.95</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:83px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">95</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:84px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">95</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:81px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">18.75</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p>&nbsp;</p>\n\n<p>&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">In table as above, last column is calculated as, % Error&nbsp;<span class=\"math-tex\">\\(=\\frac{P-Q}{Q}\\times 100.\\)</span></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">This means that too sensitive (say 5 %) setting of a ground relay does not provide that nice sensitivity when referred to primary terms. Hence, higher sensitivity should be selected when it is really required. If the ground relay is connected as shown in figure 7.13(a) or 7.13(b), the error in sensitivity will reduce as there is only one CT core. The multiplying factor, in this case, will be 1 instead of 3.</span></p>','','1','7.1.7',NULL,'1','2','1','0','1','2021-08-18 09:28:05','2021-08-18 14:58:05'),(2419,101,'7.1.8 Application Example','','single','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16253803861625380386.jpg\" style=\"height:383px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>Example 2:</strong> Figure 7.15 shows a single line diagram of a portion of a power system. Relays R<sub>1</sub>, R<sub>2</sub>&nbsp;And R<sub>3</sub> are standard IDMT overcurrent relays giving normal inverse characteristic. Each relay group is wired for three overcurrent and one earth-fault protection scheme. The setting range of ground overcurrent relays is 10-40 % of 1 amp in seven equal steps. The excitation current of all CTs is 0.05 amp. The minimum operating time for IDMT relays is constant beyond PSM = 20 and is 2.3 seconds at TMS = 1.0. The TMS of the relay R<sub>3</sub> is set at 0.2. The fault currents at different buses are as shown in table 7.5 below:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:66px; width:900px\">\n	<caption>\n	<p><span style=\"font-size:18px\"><strong>Table 7.5: Fault Currents at Different Buses</strong></span></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:102px\">\n			<div style=\"text-align:center\"><strong><span style=\"font-size:28px\">Fault at Bus</span></strong></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:124px\">\n			<div style=\"text-align:center\"><strong><span style=\"font-size:28px\">Fault Current for L-L-L fault in Amp</span></strong></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><strong><span style=\"font-size:28px\">Fault Current for L-L fault in Amp</span></strong></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><strong><span style=\"font-size:28px\">Fault Current for L-g fault in Amp</span></strong></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:102px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:124px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2100</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1818</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2714</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:102px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:124px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1580</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1366</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1653</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:102px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:124px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1264</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1094</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1192</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:102px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">D</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:124px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1054</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">912</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">928</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p>&nbsp;</p>\n\n<p>&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Determine the settings of ground relays R<sub>1</sub>, R<sub>2</sub> and R<sub>3</sub>.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong><u>Solution:</u></strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">P. S. of R<sub>3</sub> = 10 % (minimum, assumed).</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Therefore, P. S. of R<sub>3</sub> = 0.1 amp.</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">CT secondary current required to inject this current through the ground relay R<sub>3</sub> = 0.1 + 3(0.5)</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Therefore, CT secondary current at relaying point R<sub>3</sub> = 0.25 amp.</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">CT primary equivalent of this current is 25 amp (CT ratio 100/1).</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Therefore, P. S. of the ground relay R<sub>3</sub> in CT primary terms is 25 amp.</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">P. S. of the relay R<sub>2</sub>&nbsp;</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(&gt; \\frac{1.3}{1.05}\\times\\)</span>&nbsp;P. S. of relay R<sub>3</sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><sub><span class=\"math-tex\">\\(&gt;\\frac{1.3}{1.05}\\times25\\)</span></sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><sub><span class=\"math-tex\">\\(&gt; 30.95 \\)</span></sub>&nbsp;amp (CT primary)</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">This current reflected in CT secondary will be 0.103 amp (CT ratio at relaying point R<sub>2</sub> is 300/1). When excitation current (3 times 0.05) is deducted, the figure is negative. This means that minimum setting 10 % for relay R<sub>2</sub> will be certainly higher than 30.95 amp calculated above. Calculating in a different way, plug-setting 10 % mean 0.1 amp. Adding excitation current requirements of 3 CTs and transforming that secondary current to primary of 300/1 CT, the plug-setting is 75 amp which is more than 30.95 amp as required. Similarly, P. S. of R<sub>1</sub> is to be set at 10 %.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong><u>Time Settings:</u></strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong><u>Coordination of R<sub>2</sub>-R<sub>3</sub></u>:</strong> I<sub>f</sub> = 1192 amp (Current for L-g fault at bus C).</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">CT secondary equivalent, i<sub>f</sub> = 11.92 amp. Therefore, current through the ground relay R<sub>3</sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp;= 11.92 &ndash; 0.15 amp = 11.77 amp.</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Therefore, </span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">PSM of ground relay R<sub>3</sub> </span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><sub><span class=\"math-tex\">\\(=\\frac{11.77}{0.1}\\)</span></sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><sub>=117.7,</sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><sub><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\hspace{0.3cm}Top\\hspace{0.2cm}of\\hspace{0.2cm}R_3\\)</span></sub>&nbsp;&nbsp;</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp;&nbsp;<span class=\"math-tex\">\\(=\\frac{3}{log_{10}20}\\times0.2\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; = 0.46 sec.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Therefore, Top of R<sub>2</sub> = 0.71 sec. I<sub>f</sub> (1192 amp) seen in secondary of 300/1 CT = 3.973 amp.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Therefore, current through the ground relay R<sub>2</sub> = 3.82 amp.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\hspace{0.3cm}PSM\\hspace{0.2cm}of\\hspace{0.2cm}R_2\\)</span>&nbsp;= 38.2.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\frac{3}{log_{10}PSM\\hspace{0.2cm}of\\hspace{0.2cm}R_2}\\times TMS\\hspace{0.2cm}of\\hspace{0.2cm}R_2\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">=0.71.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\hspace{0.3cm}TSM\\hspace{0.1cm}of\\hspace{0.1cm}R_2\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp;&nbsp;<em>=0.308.</em>&nbsp;Hence, TMS = 0.35 selected.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong><u>R<sub>1</sub>-R<sub>2</sub> coordination:</u></strong> I<sub>f</sub> = 1653 amp. Therefore, CT secondary equivalent (300/1 CT) i<sub>f</sub> = 5.51 amp.</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Current through the ground relay R<sub>2</sub> = 5.51 &ndash; 0.15 = 5.36 amp. </span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Therefore, </span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">PSM of R<sub>2&nbsp;</sub><span class=\"math-tex\">\\(=\\frac{5.36}{0.1}\\)</span>&nbsp;= 53.6.</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Top of R<sub>2</sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><sub><span class=\"math-tex\">\\(=\\frac{3}{log_{10}20}\\times0.35\\)</span></sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><sub>= 0.807 sec,</sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\hspace{0.3cm}Top\\hspace{0.2cm}of\\hspace{0.2cm}R_1\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp;<em>=1.057 sec.</em></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">I<sub>f</sub> seen in secondary of 750/1 CT = 2.204 amp. Hence, current through ground relay R<sub>1</sub>= 2.054 amp. PSM of R<sub>1</sub> = 20.54.</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\hspace{0.3cm}TSM\\hspace{0.1cm}of\\hspace{0.1cm}R_1\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp;&nbsp;<span class=\"math-tex\">\\(=\\frac{1.057\\times log_{10}20}{3}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; = 0.458.</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Hence TMS of R<sub>1&nbsp;</sub>will be set at 0.5.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:94px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.6: Summary of Settings of Relays of Example 2</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:106px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Ground Relay</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:111px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">P.S. as % of Relay Rating</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:104px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">TMS</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:106px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>1</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:111px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">10</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:104px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.2</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:106px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>2</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:111px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">10</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:104px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.35</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:106px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>3</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:111px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">10</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:104px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.5</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>','','1','7.1.8',NULL,'1','2','1','0','1','2021-08-18 09:37:08','2021-08-18 15:07:08'),(2420,101,'7.1.9 Application Example','','single','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16253847621625384762.jpg\" style=\"height:528px; width:900px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong><u>Example 3:</u></strong> Figure 7.16 shows a power system network. Ground relays R<sub>1</sub>, R<sub>2</sub> and R<sub>3</sub> are normal inverse IDMT relays with inbuilt high-set instantaneous units. The % overreach of instantaneous units of relays is 10 %. The fault currents are tabulated below:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:57px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.7: Fault Currents at Different Buses</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:94px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault at Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:114px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for L-L-L-g Fault in Amp</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for L-L Fault in </span></div>\n\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Amp</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:113px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for L-g Fault in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; height:20px; vertical-align:top; width:94px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; height:20px; vertical-align:top; width:114px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3131</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; height:20px; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2711</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; height:20px; vertical-align:top; width:113px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3859</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; height:20px; vertical-align:top; width:94px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; height:20px; vertical-align:top; width:114px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2094</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; height:20px; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1813</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; height:20px; vertical-align:top; width:113px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2024</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:94px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:114px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2144</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1856</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:113px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2560</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:94px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">D</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:114px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1602</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1388</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:113px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1676</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p>&nbsp;</p>\n\n<p>&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Determine P. S., TMS and setting of high-set instantaneous units of ground relays R<sub>1</sub>, R<sub>2</sub> and R<sub>3</sub>. Also suggest setting of high-set instantaneous units of phase relays R<sub>1</sub>, R<sub>2</sub> and R<sub>3</sub>. Assume setting range of ground relays as 10-40 % of 1 amp and excitation current of all CTs as 0.05 amp.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong><u>Solution:</u></strong>&nbsp; TMS of R<sub>3</sub> = 0.1 (minimum, assumed)</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">TMS of R<sub>2</sub> = 0.1 (as settings of R<sub>2</sub> and R<sub>3</sub> are independent, ground relay R<sub>2</sub> is not to be graded with ground relay R<sub>3</sub> as delta-wye transformer is there between these two relays).</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">P. S. of R<sub>3</sub> = 10 % (minimum available). As there is delta-wye transformer intervening between relaying points R<sub>2</sub> and R<sub>3</sub>, these relays are not required to be coordinated and can be independently set. Therefore, P. S. of R<sub>2</sub> =10 % (minimum available).</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}P.S.of\\hspace{0.1cm}R_1\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(&gt;\\frac{1.3}{1.05}\\times P.S.\\hspace{0.1cm}of\\hspace{0.1cm}R_2\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(&gt;92.85\\)</span>&nbsp;amp (prime)</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&gt; 0.3095 amp (sec of <span class=\"math-tex\">\\(\\frac{300}{1}\\)</span>&nbsp;CT).</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">P. S. of R<sub>2</sub> in CT primary terms = 300 [0.1 + 3(0.05)] =75 amp.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Therefore, current through R<sub>1</sub> = 0.3095 &ndash; 0.15 = 0.1595 amp = 15.95 % 0f 1 amp. Hence, P. S. of R<sub>1</sub> is selected as 20 %.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><u>Settings of high-set Instantaneous units of ground relays:</u></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Setting of H. S. unit of ground relay R<sub>3&nbsp;</sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(= \\frac{100\\times B}{100-A}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(=\\frac{100\\times \\frac{1676}{300}}{100-10}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">= 6.2 amp, or 620% of 1 amp.Hence, high-set setting of 650 % selected.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Setting of H. S. unit of ground relay R<sub>2</sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(=\\frac{100\\times \\frac{2560\\times66}{\\sqrt3\\times132\\times300}}{90}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">= 2.73 amp, or 273% of 1 amp.&nbsp;Hence H. S. setting of 400 % (minimum available) is selected.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Setting of H. S. unit of R<sub>1</sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(= \\frac{100\\times \\frac{2024}{300}}{90}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">= 7.40 amp or 749% of 1 amp.&nbsp;Hence, H. S. setting 750 % suggested.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong><u>R<sub>1</sub>-R<sub>2</sub> coordination:</u></strong> I<sub>f</sub> = 2024 amp, i<sub>f</sub> (secondary equivalent) = 6.746 amp. Current through the ground relay R<sub>2</sub> will be equal to (6.746 &ndash; 0.15) 6.6 amp, or 660 % of 1 amp. This is more than high-set setting 400 %. Hence R<sub>2</sub> will operate within 0.06 sec (maximum). Therefore, Top of R<sub>1</sub> = 0.06 + .25 = 0.31 sec.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Hence TMS of R<sub>1</sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(=\\frac{0.31\\times log_{10}20}{3}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">=0.1344,&nbsp;<em>hence 0.15 selected.</em></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><u>High-set Settings of Phase Overcurrent Relays:</u></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">H. S. Setting of R<sub>3</sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(=\\frac{100\\times \\frac{1602}{300}}{90}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">= 5.93 amp or 593% of 1 amp, hence 600 % selected.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">H. S. Setting of R<sub>2</sub> &nbsp;</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(=\\frac{100\\times \\frac{2144\\times 66}{132\\times 300}}{90}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">= 3.97 amp or 397 % of 1 amp, hence 400 % selected.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">H. S. Setting of R<sub>2</sub> </span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(=\\frac{100\\times \\frac{2094}{300}}{90}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">= 7.75 amp or 775 % of 1 amp, hence 800% suggested.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.8: Summary of Settings of Relays of Example 3</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><strong><span style=\"font-size:28px\">Relay</span></strong></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><strong><span style=\"font-size:28px\">P. S. of Ground Relay in % of 1 amp</span></strong></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><strong><span style=\"font-size:28px\">TMS of Ground Relay</span></strong></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><strong><span style=\"font-size:28px\">H. S. Inst. Setting of Ground Relay in % of 1 amp</span></strong></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><strong><span style=\"font-size:28px\">H. S. Inst. Setting of Phase Relays in % of 1 amp</span></strong></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>1</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">20</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.15</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">750</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">800</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>2</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">10</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.1</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">400</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">400</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>3</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">10</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.1</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">650</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">600</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>','','1','7.1.9',NULL,'1','2','1','0','1','2021-07-04 13:16:28','2021-07-04 13:16:28'),(2421,101,'<p>7.2 Directional Overcurrent Protection</p>','','single','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16253849601625384960.jpg\" style=\"height:386px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">The radial feeder that we have been discussing so far is suffering from a major disadvantage. Refer figure 7.2. It is obvious that the loads are fed from all buses A, B, C, and D. Now, in case of fault in line section CD, relay R<sub>3</sub> will operate to trip breaker CB<sub>3</sub>. It can be very easily appreciated that all loads fed from bus D will be devoid of power. In case of fault in line section BC, relay R<sub>2</sub> will operate, CB<sub>2</sub> will open and fault will be cleared but, at the same time, all loads fed from bus C and D will not receive electric power till the fault is rectified. In case of fault in line segment AB, probably 80 % of power system will be in dark. Also, there will be a serious problem of power system instability.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16253850231625385023.jpg\" style=\"height:251px; width:800px\" /></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16253850661625385066.jpg\" style=\"height:554px; width:900px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">This problem can be solved if the same radial feeder as in figure is fed from both the ends as shown in figure 7.17. But in this case, there will be a problem of setting of overcurrent relays if simple inverse-time overcurrent relays are used. The radial system shown in figure 7.17 can be simplified to be two radial feeders fed from one end as shown in figure 7.18. In first radial network, R<sub>5</sub> is a last relay towards load. R<sub>3</sub> backs up R<sub>5</sub> and R<sub>1</sub> backs up R<sub>3</sub>. In second radial feeder, the ascending order of time setting will be of relays R<sub>2</sub>-R<sub>4</sub>-R<sub>6</sub>. The time settings are shown in terms of seconds near relays for discriminative operation of relays.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Now, if simple overcurrent relays are used, relays R<sub>1</sub>, R<sub>2</sub> and R<sub>5</sub> will operate tripping respective breakers for the fault at F<sub>1</sub>. For the fault at F<sub>2</sub>, R<sub>2</sub> and R<sub>5</sub> will operate. Similarly, for the fault at F<sub>3</sub>, R<sub>2</sub>, R<sub>5</sub> and R<sub>6</sub> would have operated. This is contrary to requirement of selectivity of protective system, as healthy feeders are isolated and loads of Buses B and C are devoid of power. Whereas, for the fault at F<sub>1</sub>, the requirement calls for tripping breakers CB<sub>1</sub> and CB<sub>2</sub> (relays R<sub>1</sub> and R<sub>2</sub> only should operate). Similarly, for fault at F<sub>2</sub>, relays R<sub>3</sub> and R<sub>4</sub> should operate as primary protection and none other. Similar is the case for fault at F<sub>3</sub>. If the breakers are made to trip for fault locations as above, only faulty feeder will be isolated and yet all loads are continued to be fed, may be with minor load shedding. This is possible only if we add one more discriminative feature, i.e., direction of fault current. If the current flows away from the bus AND if it is more than plug-setting of the relay, then only the relay should operate. If the direction of flow of the fault current is non-operative (i.e., towards the bus), the relay should block even if the current is more than plug-setting. These operative directions are shown by arrowheads in figure 7.17. It can be appreciated that, for the fault at F<sub>2</sub>, the direction of flow of fault current (fed from G<sub>1</sub>) is contrary to the operative direction for the relay R<sub>2</sub> and correct (operative) for the relay R<sub>3</sub>. Hence, R<sub>3</sub> will operate (R<sub>2</sub> will not operate) and R<sub>1</sub> will offer back-up. Similarly, for the same fault location and for fault current fed from G<sub>2</sub>, R<sub>4</sub> will operate and R<sub>5</sub> will not operate. Thus, if R<sub>2</sub>, R<sub>3</sub>, R<sub>4</sub> and R<sub>5</sub> are directional overcurrent relays, the requirement of selectivity and discrimination between faults in different sections is achieved. The directional property is not required for R<sub>1</sub> and R<sub>6</sub> as current does not reverse in these two relays for fault locations F<sub>1</sub>, F<sub>2</sub> or F<sub>3</sub>.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">The requirement of this directional discrimination is applicable in case of different power system networks depicted below:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16253851141625385114.jpg\" style=\"height:580px; width:800px\" /></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">As shown in figure 7.19, most of the transmission lines are parallel feeders running on single series of transmission towers. For fault at F<sub>1</sub>, the fault current flows in paths AF<sub>1</sub> and CDBF<sub>1</sub>. Hence R<sub>1</sub> will operate tripping CB<sub>1</sub>. Also, R<sub>3</sub> and R<sub>4</sub> will operate if the relays are simple overcurrent relays. This is contrary to requirement of selectivity of protective relaying system as healthy feeder CD will also be isolated. Top of R<sub>4</sub> cannot be set more than that of R<sub>3</sub>, as for fault at F<sub>2</sub> (when fault current flow path is ABDF<sub>2</sub>), the requirement will call for Top of R<sub>3</sub> to be more than that of R<sub>4</sub>. Therefore, TMS of both relays R<sub>3</sub> and R<sub>4</sub> are set to be same and are provided with directional discrimination. This means that relays R<sub>3</sub> and R<sub>4</sub> are directional IDMT overcurrent relays with operative direction as shown by arrowheads in figure 7.19 (fault current direction away from bus is operative for these relays) and R<sub>1</sub> and R<sub>2</sub> are non-directional simple overcurrent relays (as the direction of current flow does not reverse in these relays for faults at F<sub>1</sub> or F<sub>2</sub>). It can be appreciated that with addition of directional sense in the relays, only faulty feeder is isolated and healthy feeder keeps on feeding power to load. No doubt, the healthy feeder will be overloaded for a while until necessary load-shedding is done at load end. The transmission line can be easily overloaded (up to even 200 %) for few minutes as the insulation is air and porcelain. Porcelain can withstand high temperatures and hot air due to increase in temperature (due to overload) is replaced by cool air. For a fault at F<sub>2</sub>, if any component of switchgear at relaying point R<sub>4</sub> fail, R<sub>1</sub> will offer back-up. Similarly, R<sub>2</sub> backs up R<sub>3</sub>. This will require proper time grading while setting the relays.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16253851611625385161.jpg\" style=\"height:1056px; width:800px\" /></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">The third kind of power system network where directional discrimination is necessary is Ring Main Network as shown in figure 7.20. In this network, if there is a fault at F ( in line BC) , the fault current will pass from generator to fault via two paths:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<ol>\n	<li style=\"list-style-type:none\">\n	<ol style=\"list-style-type:lower-alpha\">\n		<li style=\"text-align:justify\">\n		<p><span style=\"font-size:14px\">Relays R<sub>1</sub> &ndash; R<sub>8</sub> &ndash; R<sub>7</sub> &ndash; F.</span></p>\n		</li>\n		<li style=\"text-align:justify\">\n		<p><span style=\"font-size:14px\">Relays R<sub>2</sub> &ndash; R<sub>3</sub> &ndash; R<sub>4</sub> &ndash; R<sub>5</sub> &ndash; R<sub>6</sub> &ndash; F.</span></p>\n		</li>\n	</ol>\n	</li>\n</ol>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16253853141625385314.jpg\" style=\"height:395px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16253853371625385337.jpg\" style=\"height:384px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">With reference to the requirement of selectivity, relays R<sub>6</sub> and R<sub>7</sub> only should operate. For fault in line AB, relays R<sub>1</sub> and R<sub>8</sub> shall operate and no other relay should operate. Hence, once again, the relays R<sub>3</sub> to R<sub>8</sub> are directional overcurrent relays (with operative direction of fault current away from the bus as shown by arrowheads in figure 7.20) and R<sub>1</sub>, R<sub>2</sub> are non-directional overcurrent relays. If directional feature is used in this way, selective tripping of breakers will occur for fault anywhere in transmission lines shown in figure 7.20. Back-up protection is also offered if proper grading of relays is carried out while relay setting exercise. For a fault at F ( in line BC), if R<sub>6</sub> fails, R<sub>4</sub> backs up and if R<sub>7</sub> fails, R<sub>1</sub> will offer back-up.&nbsp;Figure 7.21 shows cascaded parallel feeder fed from one end, which is one more application of directional discrimination in relays. The operative direction for relays is shown by arrowheads in figure 7.21. The directional requirement in cascaded parallel feeder fed from both ends is shown in figure 7.22.</span></p>','','1','7.2','Directional Overcurrent Protection','1','2','1','0','1','2021-08-18 09:40:56','2021-11-03 16:19:22'),(2422,101,'7.2.1 Directional Relays','','single','html','<p style=\"text-align:justify\"><span style=\"font-size:14px\">A directional relay measures the angle between current and voltage vectors. Torque, in a directional relay, can be expressed as,</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(T\\propto \\phi_v\\hspace{0.1cm}\\phi_i\\hspace{0.1cm}sin\\hspace{0.1cm}\\alpha\\)</span>,</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">But as&nbsp;<span class=\"math-tex\">\\(\\phi_i\\hspace{0.1cm}\\propto\\hspace{0.1cm}I\\)</span>,</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\phi_v\\hspace{0.1cm}\\propto\\hspace{0.1cm}I_v\\)</span>&nbsp;and&nbsp;<span class=\"math-tex\">\\(I_v\\hspace{0.1cm}\\propto\\hspace{0.1cm}V\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(T\\propto VI\\hspace{0.1cm}sin\\hspace{0.1cm}(90-\\phi)\\)</span></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(T\\propto VI\\hspace{0.1cm}cos\\hspace{0.1cm}\\phi\\)</span>&nbsp;(Refer figure 7.23).</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16253871031625387103.jpg\" style=\"height:652px; width:800px\" /></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16253871251625387125.jpg\" style=\"height:931px; width:800px\" /></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">The characteristic of a directional relay, using this torque equation, is shown in figure 7.24. In this figure current is shown as reference vector (X axis). Voltage vector can lie in any of the four quadrants. At an angle <span class=\"math-tex\">\\(\\phi=0^0\\)</span>,&nbsp;torque is maximum [for V = rated voltage of the relay (usually 110 V) and I = rated current of the relay (1 amp or 5 amp)]. This angle (which is zero in figure 7.24) is known as Maximum Torque Angle (MTA) or characteristic angle of the relay. The line on which the torque is maximum is known as Maximum Torque Line (M. T. Line). At&nbsp;<span class=\"math-tex\">\\(\\phi=+\\hspace{0.1cm}90^0\\hspace{0.1cm}or\\hspace{0.1cm}-\\hspace{0.1cm}90^0\\)</span>&nbsp;,&nbsp;torque is zero. The line on which torque is zero, is known as zero torque line. For any angle less than +90<sup>0</sup> and more than - 90<sup>0</sup>, the torque will be positive as shown by &ldquo;Tripping Zone&rdquo; in figure 7.24. For the angle&nbsp;&nbsp;<span class=\"math-tex\">\\(\\phi\\)</span>&nbsp;&nbsp;more than + 90<sup>0</sup> and less than - 90<sup>0</sup>,&nbsp;<span class=\"math-tex\">\\(cos\\hspace{0.1cm}\\phi\\)</span>&nbsp; will be negative and hence the relay cannot operate. This zone is shown by &ldquo;Blocking Zone&rdquo; in figure 7.24. Thus, the relay measures angle between V and I, irrespective of magnitudes of V and I. Hence directional relay is a phase comparator relay.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Certain minimum voltage V<sub>min</sub> (shown in figure 7.24) is required at any angle &Oslash;&nbsp;(from - 90<sup>0</sup> to + 90<sup>0</sup>) to make the relay operative. As, if V = 0, torque will be zero and hence the relay cannot operate. At fault point, V = 0. Hence, if fault occurs immediately after relaying point (in an operative direction), voltage measured by the relay (V = I Z) is zero and hence the relay does not operate. This means that some minimum voltage V<sub>min</sub> is required to make the relay operative. In electromechanical relays, actuating mechanism has to compensate for frictional torque and a slight spring bias. Hence, this voltage is comparatively larger than that in case of static or numerical relays. The value of this voltage (at rated current and MTA) is known as directional sensitivity and is usually expressed in terms of % of V<sub>R</sub>, rated voltage. It is usually 1 % in electromagnetic relays.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">As V = I Z, minimum voltage requirement in directional units mean minimum impedance of line. This means that certain minimum length (as Z is proportional to line length) of line from relaying point is not protected, howsoever the direction of fault current is correct (operative). This length is known as dead zone as shown in figure 7.24.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Directional overcurrent relay is an AND logic of a directional relay and an overcurrent relay. Hence the relay operates only if direction of fault current is correct (operative) and current is more than plug-setting of the relay. If fault current flows in a direction contrary to operative direction, the relay does not operate even if current is more than its plug-setting.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">As such, the characteristic angle (or MTA),&nbsp;<span class=\"math-tex\">\\(\\theta=0^0\\)</span>&nbsp;(as shown in the figure 7.24) has no meaning. When fault occurs, the angle between V and I vector is to the tune of 70<sup>0</sup> to 90<sup>0</sup> depending on fault location. Hence, directional relays should provide maximum torque at this angle. Therefore, the MTA of the directional relay should be of the same order. Torque of the directional relay, in this case,</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(T\\propto VI\\hspace{0.1cm}cos\\hspace{0.1cm}(\\phi-\\theta)\\)</span></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16292797431629279743.jpg\" style=\"height:555px; width:800px\" /></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16253872381625387238.jpg\" style=\"height:627px; width:800px\" /></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">The characteristic of such a directional relay is given in figure 7.25(b). If&nbsp;<span class=\"math-tex\">\\(\\theta\\)</span>&nbsp;=&nbsp;90<sup>0</sup> and for a fault location such that&nbsp;<span class=\"math-tex\">\\(\\phi\\)</span>&nbsp;=&nbsp;75<sup>0</sup>,&nbsp;<span class=\"math-tex\">\\(T\\propto VI\\hspace{0.1cm}cos\\hspace{0.1cm}15\\)</span>.&nbsp;</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Hence about 96 % of maximum torque is available at relaying point. Therefore, usually MTA is adjusted at 90<sup>0</sup>. Exact angle can be calculated by using fault calculations discussed earlier and can be set in numerical relays. Wide range of adjustment is provided in numerical relays (in steps of 1<sup>0</sup>).</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">MTA can be set at 30<sup>0</sup>, 60<sup>0</sup> or 90<sup>0</sup> by suitable connections of CTs and PTs. As 90<sup>0</sup> connection is widely used, it will be discussed here. Quantities fed to directional relays in case of 90<sup>0</sup> connection are tabulated below:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:76px; width:900px\">\n	<caption>\n	<p><span style=\"font-size:18px\"><strong>Table 7.9: Quantities to be Fed to Phase Units of Direction Relays</strong></span></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:125px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Relay</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:121px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Current</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:104px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Voltage</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:125px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R phase</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:121px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">I<sub>R</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:104px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">V<sub>YB</sub></span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:125px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Y phase</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:121px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">I<sub>Y</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:104px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">V<sub>BR</sub></span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:125px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B phase</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:121px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">I<sub>B</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:104px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">V<sub>RY</sub></span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p>&nbsp;</p>\n\n<p>&nbsp;</p>\n\n<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16253872981625387298.jpg\" style=\"height:856px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">The vector diagram showing 90<sup>0</sup> connection is illustrated in figure 7.26. The diagram is drawn with unity power factor consideration. As vector I<sub>R</sub> leads vector V<sub>YB</sub> (similar is the relation between I<sub>Y</sub> - V<sub>BR</sub> and I<sub>B</sub> - V<sub>RY</sub>) by 90<sup>0</sup>, the connection gets the name 90<sup>0</sup> connection. When fault occurs I<sub>R</sub> will lag V<sub>R</sub> by approximately 90<sup>0</sup> providing maximum torque [as I<sub>R</sub> (under fault condition) will be in phase with V<sub>YB</sub>].</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Now, if there is R-Y fault immediately after relaying point, R-phase and Y-phase units will sense a fault. For R-Y fault V<sub>RY</sub> = 0 and as fault has occurred immediately after relaying point, V<sub>RY</sub> measured by the relay is zero. But the voltages fed to R and Y units are V<sub>YB</sub> and V<sub>BR</sub> respectively which are not zero. (Similar argument holds good for Y-B fault and B-R fault also). Hence, there is no dead zone in case of L-L faults if 90<sup>0</sup> connection is used.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">A directional earth-fault unit is fed with residual current and open delta (residual) voltage. As V<sub>R</sub> + V<sub>Y</sub> + V<sub>B</sub> = 0 under normal condition, under the conditions of L-L-L faults and in case of L-L fault, directional earth-fault unit measures angle between the quantities fed to it only in case of L-g and L-L-g faults. In case of L-g faults, the residual voltage is equal to depression of voltage in faulted phase for effectively earthed systems. This voltage causes the earth-fault relay to operate if residual current is more than plug-setting of a relay and the phase angle between residual voltage and residual current is within the range &ndash;90<sup>0</sup> to + 90<sup>0</sup> (i.e., direction is operative) as discussed. In case of R-g fault immediately after relaying point, V<sub>Rg</sub> = 0. But voltage fed to relay (V<sub>R</sub> + V<sub>Y</sub> + V<sub>B</sub> = V<sub>Y</sub> + V<sub>B</sub>) is not equal to zero. Similar argument holds good for Y-g and B-g faults too). Hence there is no dead zone in case of L-g faults too. Dead zone is found only for L-L-L-g faults (0.2 % probability) in which case one has to depend on remote back-up relay only. The detailed protective scheme of directional overcurrent protection of transmission line is shown in figure 7.27.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16253873411625387341.jpg\" style=\"height:726px; width:800px\" /></span></p>','','1','7.2.1',NULL,'1','2','1','0','1','2021-08-18 09:42:43','2021-08-18 15:12:43'),(2423,102,'1 Introduction of Programme','','single','single','https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16254580231625458023.mp4','','1','1',NULL,'1','2','1','0','1','2021-07-05 09:37:03','2021-07-05 09:37:03'),(2424,102,'2 Introduction of Faculty','','single','single','https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16254582371625458237.mp4','','1','2',NULL,'1','2','1','0','1','2021-07-05 09:40:37','2021-07-05 09:40:37'),(2425,102,'3 Commandments for closing a sale','','single','single','https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16254589711625458971.mp4','','1','3',NULL,'1','2','1','0','1','2021-07-05 09:52:52','2021-07-05 09:52:52'),(2426,102,'In order to present a proposal, make sure to carry .............','','multi','single','','','1','3',NULL,'3','1','1','0','1','2021-07-05 04:27:49','2021-07-05 09:57:49'),(2427,102,'What is a discipline instilled only through practice?','','multi','single','','','1','3',NULL,'1','1','1','0','1','2021-07-05 10:01:21','2021-07-05 10:01:21'),(2428,102,'What an eye contact with the prospects suggests?','','multi','single','','','1','3',NULL,'2','2','1','0','1','2021-07-05 10:02:39','2021-07-05 10:02:39'),(2429,102,'What all agreements requires?','','multi','single','','','1','3',NULL,'3','1','1','0','1','2021-07-05 10:04:13','2021-07-05 10:04:13'),(2430,102,'When we leave the customer to check on something, what it creates in their mind?','','multi','single','','','1','3',NULL,'3','1','1','0','1','2021-07-05 10:06:16','2021-07-05 10:06:16'),(2431,102,'What is a million dollar tip?','','multi','single','','','1','3',NULL,'4','1','1','0','1','2021-07-05 10:08:49','2021-07-05 10:08:49'),(2432,102,'What is everything when it comes to closing the deal?','','multi','single','','','1','3',NULL,'2','1','1','0','1','2021-07-05 10:23:13','2021-07-05 10:23:13'),(2433,102,'If your prospects stands up, what you should do?','','multi','single','','','1','3',NULL,'1','1','1','0','1','2021-07-05 10:27:22','2021-07-05 10:27:22'),(2434,102,'You should always present a proposal in?','','multi','single','','','1','3',NULL,'2','1','1','0','1','2021-07-05 10:30:53','2021-07-05 10:30:53'),(2435,102,'Everyone trusts a person, who communicates ............','','multi','single','','','1','3',NULL,'3','1','1','0','1','2021-07-05 10:32:18','2021-07-05 10:32:18'),(2436,102,'What is vital to make with your prospects?','','multi','single','','','1','3',NULL,'1','1','1','0','1','2021-07-05 10:33:35','2021-07-05 10:33:35'),(2437,102,'Humour should make people feel?','','multi','single','','','1','3',NULL,'4','1','1','0','1','2021-07-05 10:36:27','2021-07-05 10:36:27'),(2438,102,'How you should treat a buyer?','','multi','single','','','1','3',NULL,'3','1','1','0','1','2021-07-05 10:38:24','2021-07-05 10:38:24'),(2439,102,'What is require to eliminate in order to reach an agreement?','','multi','single','','','1','3',NULL,'2','1','1','0','1','2021-07-05 10:43:08','2021-07-05 10:43:08'),(2440,102,'Negativity always succumbs to ...........','','multi','single','','','1','3',NULL,'3','1','1','0','1','2021-07-05 10:44:14','2021-07-05 10:44:14'),(2441,103,'1 Introduction of Programme','','single','single','https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16254653271625465327.mp4','','1','1',NULL,'1','2','1','0','1','2021-07-05 11:38:47','2021-07-05 11:38:47'),(2442,103,'2 Introduction of Faculty','','single','single','https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16254653971625465397.mp4','','1','2',NULL,'1','2','1','0','1','2021-07-05 11:39:58','2021-07-05 11:39:58'),(2443,103,'3 Types Of E-Commerce','','single','single','https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16254655571625465557.mp4','','1','3',NULL,'1','2','1','0','1','2021-07-05 11:42:38','2021-07-05 11:42:38'),(2444,103,'4 How To Get Contact Details Of Overseas Buyers','','single','single','https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16254656451625465645.mp4','','1','4',NULL,'1','2','1','0','1','2021-07-05 11:44:07','2021-07-05 11:44:07'),(2445,103,'5 Government Source','','single','single','https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16254657241625465724.mp4','','1','5',NULL,'1','2','1','0','1','2021-07-05 11:45:25','2021-07-05 11:45:25'),(2446,103,'6 Begin With……','','single','single','https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16254658361625465835.mp4','','1','6',NULL,'1','2','1','0','1','2021-07-05 11:47:17','2021-07-05 11:47:17'),(2447,103,'How many types of E-commerce','','multi','single','','','1','3',NULL,'4','1','1','0','1','2021-07-05 11:52:47','2021-07-05 11:52:47'),(2448,103,'Which of the following consumers will have a wide and direct access to producers of goods and services without intermediaries?','','multi','single','','','1','3',NULL,'1','1','1','0','1','2021-07-05 11:53:54','2021-07-05 11:53:54'),(2449,103,'How to Get Contact Details of Overseas Buyers?','','multi','single','','','1','4',NULL,'3','2','1','0','1','2021-07-05 11:55:07','2021-07-05 11:55:07'),(2450,103,'Countries which are economically advanced and technologically advanced','','multi','single','','','1','5',NULL,'4','1','1','0','1','2021-07-05 06:40:08','2021-07-05 12:10:08'),(2451,103,'Countries which are economically advanced and technologically poor','','multi','single','','','1','5',NULL,'4','1','1','0','1','2021-07-05 06:39:32','2021-07-05 12:09:32'),(2452,103,'Countries which are technologically advanced and economically poor','','multi','single','','','1','5',NULL,'4','1','1','0','1','2021-07-05 06:38:59','2021-07-05 12:08:59'),(2453,103,'Countries which are economically poor and technologically poor','','multi','single','','','1','5',NULL,'4','1','1','0','1','2021-07-05 06:38:32','2021-07-05 12:08:32'),(2454,103,'Which of the following is important to find? (Extra space between find and  Removed ?)','','multi','single','','','1','6',NULL,'1','2','1','0','1','2021-07-05 12:07:24','2021-07-05 12:07:24'),(2455,104,'1 Introduction of Programme','','single','single','https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16254723521625472352.mp4','','1','1',NULL,'1','2','1','0','1','2021-07-05 08:05:53','2021-07-05 13:35:53'),(2456,104,'2 Introduction of Faculty','','single','single','https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16254724241625472424.mp4','','1','2',NULL,'1','2','1','0','1','2021-07-05 13:37:05','2021-07-05 13:37:05'),(2457,104,'3 Trade related Cargo Insurance','','single','single','https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16254726381625472638.mp4','','1','3',NULL,'1','2','1','0','1','2021-07-05 13:40:40','2021-07-05 13:40:40'),(2458,104,'Class certificate is approved by_____?','','multi','single','','','1','3',NULL,'2','1','1','0','1','2021-07-05 13:43:47','2021-07-05 13:43:47'),(2459,104,'When are the ships considered as unseaworthy?','','multi','single','','','1','3',NULL,'1','1','1','0','1','2021-07-05 13:45:31','2021-07-05 13:45:31'),(2460,104,'Do marine insurance gives claim which arise due to sinking of the vessel due to age factor?','','multi','single','','','1','3',NULL,'1','1','1','0','1','2021-07-05 13:47:32','2021-07-05 13:47:32'),(2461,104,'Who has the right to claim as unpaid vendor?','','multi','single','','','1','3',NULL,'3','1','1','0','1','2021-07-05 13:53:01','2021-07-05 13:53:01'),(2462,104,'Insurance document is issued and signed by____?','','multi','single','','','1','3',NULL,'4','1','1','0','1','2021-07-05 13:54:47','2021-07-05 13:54:47'),(2463,104,'A minimum amount of loss that is incurred before insurance coverage applies is called?','','multi','single','','','1','3',NULL,'2','1','1','0','1','2021-07-05 13:56:38','2021-07-05 13:56:38'),(2464,104,'Section____of Marine Insurance Act allows assignment unless it is prohibited under the terms of policy?','','multi','single','','','1','3',NULL,'1','1','1','0','1','2021-07-05 13:58:01','2021-07-05 13:58:01'),(2465,104,'Is it true, Incoterm 2020 makes compulsory for either buyer or seller to take insurance?','','multi','single','','','1','3',NULL,'3','1','1','0','1','2021-07-05 14:01:06','2021-07-05 14:01:06'),(2466,104,'Can the shipper claim for the loss incurred due to  war, strikes or riots?','','multi','single','','','1','3',NULL,'3','1','1','0','1','2021-07-05 14:04:42','2021-07-05 14:04:42'),(2467,104,'What are neo bulk?','','multi','single','','','1','3',NULL,'1','1','1','0','1','2021-07-05 14:08:21','2021-07-05 14:08:21'),(2468,104,'Motor Driving Acts prescribe compulsory_____insurance?','','multi','single','','','1','3',NULL,'4','1','1','0','1','2021-07-05 14:10:57','2021-07-05 14:10:57'),(2469,104,'________Claim satisfy obligation of Realization of Export Payment due to failure of Importer to make payment?','','multi','single','','','1','3',NULL,'2','1','1','0','1','2021-07-05 14:12:42','2021-07-05 14:12:42'),(2470,104,'Which insurance cover requires all other cargo holding owners on ship to pay compensation to periled cargo owner?','','multi','single','','','1','3',NULL,'2','1','1','0','1','2021-07-05 14:15:20','2021-07-05 14:15:20'),(2471,104,'When selling on CFR terms the seller is liable only till____?','','multi','single','','','1','3',NULL,'1','1','1','0','1','2021-07-05 14:17:05','2021-07-05 14:17:05'),(2472,104,'Under CFR terms claim payment is made to _____and buyer is the______?','','multi','single','','','1','3',NULL,'3','1','1','0','1','2021-07-05 14:20:02','2021-07-05 14:20:02'),(2473,101,'7.2.2 Application Example','','single','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16255624931625562493.jpg\" style=\"height:421px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong><u>Example 4:</u></strong> Figure 7.28 shows a single line diagram of a portion of a power system network. Bracketed figures near the bus give the fault levels for a triple line fault on the concerned bus. Relays used are IDMT overcurrent and earth-fault relays rated for 1 amp with a setting range as follows:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Overcurrent Phase Units: 50 &ndash; 200 % of 1 amp in 7 equal steps.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Overcurrent Earth-fault Units: 10-40 % of 1 amp in 7 equal steps.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Both phase and ground units at relaying point R<sub>7</sub> are set for TMS = 0.25. Relays R<sub>1</sub>, R<sub>2</sub>, R<sub>3</sub> and R<sub>4</sub> are voltage-controlled overcurrent relays such that their plug-setting reduces to 40 % of the set value if voltage reduces below 70 % of rated voltage. The excitation currents of all CTs are 0.03 amp. The magnitudes of earth-fault currents at different buses are as follows:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Bus A: 5014 amp.</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Bus B: 3288 amp.</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Bus C: 4445 amp.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Assuming suitable discrimination time margin, determine the plug-settings and time settings of all phase and ground relays shown in figure.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong><u>Solution:</u></strong> It can be observed that Relays R<sub>5</sub> and R<sub>6</sub> are directional overcurrent relays and other relays are non-directional overcurrent relays. Now, plug-settings are to be calculated first.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong><u>Plug-Settings of Phase Relays:</u></strong> Plug-setting of R<sub>7</sub> will be decided based on the rated primary current of 100 MVA transformer.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">P.S. of R<sub>7&nbsp;</sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(=\\frac{100\\times10^3\\times 100}{\\sqrt3\\times132\\times 500}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">= 87.47 %. </span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">hence,100% shall be set.&nbsp;It can be appreciated that R<sub>3</sub>/R<sub>4</sub> will back-up relay R<sub>7</sub>. P. S. of R<sub>3</sub>/R<sub>4</sub> for grading with the relay R<sub>7</sub> will be 75 % ( <span class=\"math-tex\">\\(\\frac{1.3}{1.05}\\)</span>&nbsp;principle).&nbsp;). The full load current per feeder is&nbsp;<span class=\"math-tex\">\\(\\frac{150\\times 10^3}{\\sqrt3\\times 132}\\)</span>&nbsp;= 656 amp.Hence, it seems that 75 % is the correct setting for relay R<sub>3</sub>/R<sub>4</sub>. But this is not so, as, when one of the feeder trips due to fault in that feeder (one line contingency), the other feeder will be loaded with double the current calculated above. Because the plug-setting is 750 amp (primary) and the load current is 1312 amp (2&times;&nbsp;656), the other feeder will also trip which is not as per requirement of protective relaying as tripping of healthy feeder is undesirable. Hence, based on single line contingency, the plug-setting of the relay R<sub>3</sub>/R<sub>4</sub> shall be set as&nbsp;<span class=\"math-tex\">\\(\\frac{1312\\times100}{1000}\\)</span>&nbsp;or&nbsp;131.2 %, i.e., 150 % is selected. Now, as R<sub>3</sub> backs up R<sub>6</sub> and R<sub>4</sub> backs up R<sub>5</sub>,</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">P.S. of R<sub>3&nbsp;</sub>or R<sub>4&nbsp;</sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&gt;&nbsp;<span class=\"math-tex\">\\(\\frac{1.3}{1.05}\\)</span>&nbsp;&times;&nbsp;P.S. of R<sub>6&nbsp;</sub>or R<sub>5&nbsp;</sub></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\)</span>&nbsp;&nbsp;P.S. of R<sub>5&nbsp;&nbsp;</sub>(or R<sub>6</sub> ) &nbsp;&nbsp;</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &lt;&nbsp;<span class=\"math-tex\">\\(\\frac{1.05}{1.3}\\)</span>&nbsp;&times; P.S. of R<sub>3&nbsp;</sub>(or R<sub>4 </sub>)</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&lt;&nbsp;<span class=\"math-tex\">\\(\\frac{1.05}{1.3}\\)</span>&nbsp;&times; 1500</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&lt; 1211.153 amp or 121.15% CT rating.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Hence, 100 % is selected.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">On the similar considerations </span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">(<span class=\"math-tex\">\\(\\frac{1.3}{1.05}\\)</span>&nbsp;principle),</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">P. S. of R<sub>1</sub>/R<sub>2</sub> shall be set at 200 %.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong><u>Plug-Settings of Ground Relays:</u></strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">P. S. of ground relay R<sub>7</sub> = 10 % (minimum available) = 0.1 amp (secondary).</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Adding excitation current requirements, CT secondary current = 0.19 amp (0.1 + 3 times 0.03).</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">P. S. of R<sub>7</sub> in CT primary terms = 95 amp.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">P. S. of ground relay R<sub>3</sub>/R<sub>4&nbsp;</sub>=<span class=\"math-tex\">\\(\\frac{1.3}{1.05}\\)</span>&nbsp;&times; 95 -117.62 amp.&nbsp;Secondary equivalent of this current &nbsp;is&nbsp;<span class=\"math-tex\">\\(\\frac{117.62}{1000}\\)</span>&nbsp;or 0.1176 amp. Hence, current being injected in ground relay R<sub>3</sub>/R<sub>4</sub> = 0.1176 &ndash; 0.09 = 0.027 amp or&nbsp;2.76 % of 1 amp. Hence, P. S. can be set (for R<sub>3</sub>/R<sub>4</sub>) at 10 %. But, as R<sub>3</sub> backs up R<sub>6,</sub> R<sub>6</sub> will be required to be set a step downwards with reference to relay R<sub>3</sub>. Therefore, ground relays R<sub>3</sub>/R<sub>4</sub> will be set at&nbsp;P. S. equal to 15 % and ground relays R<sub>5</sub>/R<sub>6</sub> will be set at plug-setting equal to 10 %. On similar line of calculations, P. S. of ground relays R<sub>1</sub>/R<sub>2</sub> is required to be set at 25 %.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong><u>Time settings of Phase Overcurrent relays:</u></strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">While deciding the time setting, worst consideration is highest fault current. The fault current will be maximum when both the feeders are in circuit. Hence, in following calculations, we will consider both the feeders in circuit.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">R<sub>3</sub>-R<sub>7</sub> coordination: Fault MVA = 700 MVA.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Therefore, PSM of R<sub>7&nbsp;</sub><span class=\"math-tex\">\\(= \\frac{700\\times 10^3}{\\sqrt3\\times132\\times500}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;= 6.12.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\)</span>&nbsp;Top of R<sub>7&nbsp;</sub><span class=\"math-tex\">\\(=\\frac{3}{log_{10}6.12}\\)</span>&nbsp;&times; 0.25</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;= 0.9532 sec.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Therefore, Top of R<sub>3&nbsp;</sub>= 0.9532 + 0.25 </span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; = 1.203 sec. </span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">PSM of R<sub>3</sub> =&nbsp;<span class=\"math-tex\">\\(\\frac{700\\times10^3}{\\sqrt3\\times 132\\times 2\\times 1500\\times 0.4}\\)</span>&nbsp;</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;= 2.55.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">This is because fault current is divided into two equal paths and relay R<sub>3</sub> is a voltage-controlled overcurrent relay, the plug-setting of which is reduced to 40 % of set value (150 % or 1500 amp) during fault condition.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\)</span>&nbsp;TMS&nbsp;of R<sub>3&nbsp;</sub><span class=\"math-tex\">\\(=\\frac{1.203\\times log_{10}2.55}{3}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; = 0.1631.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Hence TMS (R<sub>3</sub>) shall be set at 0.2. same will be the TMS of&nbsp;R<sub>4&nbsp;</sub></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">R<sub>3</sub>-R<sub>6</sub> coordination: Fault current will be same. </span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Top of R<sub>3&nbsp;</sub><span class=\"math-tex\">\\(=\\frac{3}{log_{10}2.55}\\)</span>&nbsp;&times; 0.2&nbsp;</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;= 1.475 sec.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Hence, Top of R<sub>6</sub> = 1.475 &ndash; 0.25 =1.226 sec. </span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">PSM of R<sub>6&nbsp;</sub><span class=\"math-tex\">\\(=\\frac{700\\times10^3}{\\sqrt3\\times 132\\times 2\\times 1000}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;= 1.53.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\)</span>&nbsp; TMS of R<sub>6&nbsp;</sub><span class=\"math-tex\">\\(= \\frac{1.226\\times log_{10}1.53}{3}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; = 0.075.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Hence, TMS(R<sub>6</sub>) shall be set at 0.05. same will be the TMS of&nbsp;R<sub>5&nbsp;</sub>.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">R<sub>1</sub>-R<sub>3</sub> coordination: Fault MVA =1000 MVA.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">PSM of R<sub>3</sub> = 7.29. </span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Therefore, Top of R<sub>3</sub> = 0.6954 sec.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\)</span>&nbsp;Top of&nbsp;R<sub>1&nbsp;</sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; = 0.9454 sec.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">PSM of R<sub>1</sub> = 2.73. Hence, TMS of R<sub>1</sub> (and R<sub>2</sub> also) = 0.1374. Hence 0.15 selected.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong><u>Time Settings of Ground Overcurrent Relays:</u></strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">R<sub>3</sub>-R<sub>7</sub> coordination: Fault current =3288 amp. Secondary equivalent, </span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(i_f= \\frac{3288}{500}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp;= 6.576 amp.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Current through the ground relay = 6.486 amp. </span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Therefore, PSM of R<sub>7&nbsp;</sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;<span class=\"math-tex\">\\(=\\frac{6.486}{0.1}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; = 64.86.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\)</span>&nbsp;Top of&nbsp;R<sub>7&nbsp;</sub><span class=\"math-tex\">\\(=\\frac{3}{log_{10}20}\\)</span>&nbsp;&times; 0.25.</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;= 0.5764 sec.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\)</span>&nbsp;Top of&nbsp;R<sub>3&nbsp;&nbsp;</sub>= 0.8264 sec.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Secondary fault current through CT secondary of relaying point R<sub>3</sub> = 1.644 amp. </span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Current through the ground relay R<sub>3</sub> = 1.554 amp. PSM of R<sub>3</sub> = 10.36.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Therefore, TMS of R<sub>3&nbsp;</sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <span class=\"math-tex\">\\(= \\frac{0.8264\\times log_{10}10.36}{3}\\)</span>&nbsp;&nbsp;</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;= 0.2796. Hence, TMS (R<sub>3</sub>) is to be at 0.3.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Top of R<sub>3</sub> = 0.8863 sec. Hence, Top of R<sub>6</sub> = 0.6363 sec. PSM of R<sub>6</sub> = 15.54.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Therefore, TMS of R<sub>6</sub> = 0.2527. Hence 0.25 selected. Similarly, TMS of R<sub>1</sub>/R<sub>2</sub> = 0.3092.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Therefore, TMS is selected as 0.35.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.10: Summary of Settings of Relays of Example 4</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Relay</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">P. S. of Phase Relay in</span></div>\n\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">&nbsp;% of 1 amp</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">TMS of Phase Relay</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">P. S. of Ground Relay in</span></div>\n\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">% of 1 amp</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">TMS of Ground Relay</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>1</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">200</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.15</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">25</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.35</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>2</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">200</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.15</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">25</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.35</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>3</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">150</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.2</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">15</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.3</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>4</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">150</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.2</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">15</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.3</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>5</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">100</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.05</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">10</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.25</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>6</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">100</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.05</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">10</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.25</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>7</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">100</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.25</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">10</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.25</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"text-align:justify\">&nbsp;</p>','','1','7.2.2',NULL,'1','2','1','0','1','2021-08-18 09:44:23','2021-08-18 15:14:23'),(2474,101,'<p>7.3 Coordination of Overcurrent and Earth-fault Relays in an Interconnected Power System</p>','','single','html','<p style=\"text-align:justify\"><span style=\"font-size:14px\">In preceding sections, the settings of overcurrent and earth-fault relays are calculated in case of radial feeder or parallel feeder networks fed from source at one end only. However, actual power system networks are interconnected having sources at multiple ends. The procedure of calculating settings of overcurrent and earth-fault relays is quite complicated and will involve the use of certain algorithms and a digital computer. We will not enter into these computer algorithms but will certainly solve the setting problems of comparatively simple interconnected networks so that the complicacy can be appreciated. The following steps are required to be followed for solving any problem of setting of overcurrent relays in an interconnected power system:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<ol>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Power-flow Analysis: The active and reactive power (P + j Q) flowing in every transmission line is to be calculated. Gauss-Seidel method, Newton-Raphson method and Fast Decoupled method are well-known methods for load flow analysis. But the requirement is yet complex. For a directional relay under consideration, it will be required to find out the configuration of network that makes the maximum current to flow through the relay in operative direction. For this purpose, line contingencies are to be considered. Usual practice is to consider single line contingency (tripping of one line at a time). This means 50 load-flow calculations for each relay if there are 50 transmission lines in a network. That is the reason why computer is required to suggest the worst</span></p>\n	</li>\n</ol>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">(i.e., one offering the maximum load current) configuration.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<ol start=\"2\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Fault Current Calculations: The fault currents for L-L-L-g and L-g faults at each bus are required to be calculated. Once again, this requires multiple calculation exercises for single line contingency as discussed. The highest of the fault currents so calculated is to be used for a given relay.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Finding out Primary-Backup Pairs in a power system network: If there are 50 transmission lines in a power system network, there will be 100 overcurrent and 100 earth-fault relays. A relay under consideration may be backed up by (say) 11 (or more or less) relays. The back-up relay that is going to operate fastest shall operate 0.25 second later than a primary relay under consideration. Even if a single relay is missed, it may lead to series of unwanted operations of protective relaying system. Hence, a computer algorithm is resorted to for finding out primary-backup relay pairs. A well-known tool for the purpose is a Link-net structure using three one-dimensional vectors, namely, LIST (bus), NEXT (relay) and FAR (relay).</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Calculation of Plug-Setting.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Calculation of Time Setting.</span></p>\n	</li>\n</ol>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Now, we will calculate the relay settings for the simplest interconnected network containing only two buses, two transmission lines and four overcurrent relays. The reader will appreciate the complicacy involved and hence understand how complicated would be, the relay setting exercise in a state grid having 50 lines and 100 relays.</span></p>','','1','7.3','Coordination of Overcurrent and Earth-fault Relays in an Interconnected Power System','1','2','1','0','1','2021-07-06 14:39:59','2021-11-03 16:20:15'),(2475,101,'7.3.1 Application Example','','single','html','<p><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16255626991625562699.jpg\" style=\"height:588px; width:800px\" /></p>\n\n<p>&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><u>Example 5:</u> Figure 7.29 shows a single line diagram of a simple interconnected power system network. Relays R<sub>1</sub> to R<sub>4</sub> are directional normal inverse overcurrent relays wired for three overcurrent and one earth-fault units. Overcurrent units have the range 50-200 % of 1 amp in seven equal steps for setting. The ground units have the range 10-40 % of 1 amp in seven equal steps for setting. The loads at both the buses are shown in the figure. Fault currents for faults at F<sub>1</sub> and F<sub>2</sub> are tabulated below:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.11: Fault Currents for Faults at F1 and F2</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">CT</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Triple Line Fault at F<sub>1</sub> in Amp</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Triple Line Fault at F<sub>2</sub> in Amp</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for L-g Fault at F<sub>1</sub> in Amp</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for L-g Fault at F<sub>2</sub> in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">CT<sub>1</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">6852</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1910</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">7933</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2088</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">CT<sub>2</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1410</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1910</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1633</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2088</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">CT<sub>3</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1410</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1910</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1633</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2088</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"margin-left:48px; text-align:center\"><span style=\"font-size:28px\">CT<sub>4</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1410</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">5539</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1633</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<p style=\"text-align:center\"><span style=\"font-size:11pt\">6059</span></p>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p>&nbsp;</p>\n\n<p>&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Assume that 10 % of power generated is used to run the auxiliaries. The phase relays R<sub>1</sub> to R<sub>4</sub> are voltage-controlled overcurrent relays such that their P. S. will reduce to 40 % of set value when voltage collapses below 70 % of rated value. The excitation current of all the CTs is 0.05 amp. Determine the settings of overcurrent and earth-fault units of relays R<sub>1</sub> to R<sub>4</sub>.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong><u>Solution:</u></strong> The operative direction of directional relays is shown by arrowheads in the figure.</span></p>\n\n<p><span style=\"font-size:14px\">Power-flow analysis: For phase relay R<sub>1</sub>/R<sub>2</sub>, considering single line contingency, the maximum possible load is 600 MW and the generation available is 0.9 ( 210 &times;&nbsp;3) or 567 MW. Hence, plug-setting of R<sub>1</sub>/R<sub>2</sub> is to be decided based on 567 MW.</span></p>\n\n<p>&nbsp;</p>\n\n<p><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\)</span>&nbsp;P.S. of R<sub>1&nbsp;</sub>or R<sub>2&nbsp;</sub></span></p>\n\n<p><span style=\"font-size:14px\"><sub>&nbsp; &nbsp; &nbsp; &nbsp;&nbsp;</sub><span class=\"math-tex\">\\(=\\frac{567\\times 10^3\\times 100}{\\sqrt3\\times220\\times 0.85\\times1500}\\)</span></span></p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">= 116.70 %. Hence, 125 % is selected.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">Similarly, P. S. of R<sub>3</sub>/R<sub>4</sub> is to be decided based on 350 MW load [because the generation 0.9&nbsp;( 210 &times; 2)&nbsp;or 378 MW is more than the load) considering single line contingency.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">P.S. of R<sub>3&nbsp;</sub>or R4&nbsp;</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(= \\frac{350\\times10^3\\times100}{\\sqrt3\\times220\\times0.85\\times1000}\\)</span>&nbsp;</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">= 108.06 %. Hence, 125 %&nbsp;is selected.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<ol start=\"2\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Fault Current Calculations: These are done and tabulated as given in table 7.11.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Primary-backup pairs: We do not need any computer algorithm to find out primary-backup pairs as it can be very easily seen in the figure. These are tabulated below:</span></p>\n	</li>\n</ol>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:208px; width:900px\">\n	<caption>\n	<p><span style=\"font-size:18px\"><strong>Table 7.12: Primary-Backup pairs of Figure 7.29</strong></span></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:105px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Primary Relay</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:103px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Back-up Relay</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:105px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>1</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:103px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>4</sub></span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:105px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>2</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:103px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>3</sub></span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:105px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>3</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:103px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>2</sub></span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:105px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>4</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:103px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>1</sub></span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p>&nbsp;</p>\n\n<p>&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">It is interesting to note that R<sub>1</sub> and R<sub>4</sub> give back-up to each other. Similarly, R<sub>2</sub> and R<sub>3</sub> give back-up to each other.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<ol start=\"4\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Calculation of Plug-Settings of Phase Relays: This is carried out at serial number 1 above.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Calculation of Time Settings of Phase Relays: As there is no last relay towards load in this system, we will start with any one relay at random, say relay R<sub>1</sub>. Consider the triple line fault at F<sub>1</sub>. </span></p>\n	</li>\n</ol>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">PSM of R<sub>1&nbsp;</sub><span class=\"math-tex\">\\(=\\frac{6852}{1.25\\times1500\\times0.4}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;= 9.136.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\)</span>&nbsp;Top of R<sub>1&nbsp;</sub><span class=\"math-tex\">\\(=\\frac{3}{log_{10}9.136}\\times 0.1\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; = 0.3123 sec.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">This is because we start with TMS of R<sub>1</sub> as 0.1. Hence, Top of back-up relay R<sub>4</sub> = 0.3123 + 0.25 = 0.5623 sec.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">PSM of R<sub>4</sub> for fault at F<sub>1</sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp;<span class=\"math-tex\">\\(=\\frac{1410}{1.25\\times1000\\times 0.4}\\)</span>&nbsp; =&nbsp; 2.82.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\)</span>&nbsp;TMS&nbsp;of R<sub>4</sub></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><sub>&nbsp;</sub><span class=\"math-tex\">\\(=\\frac{0.5623\\times log_{10}2.82}{3}\\)</span></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; = 0.084.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Therefore, TMS (R<sub>4</sub>) shall be set at 0.1, according to this calculation. But the setting exercise is yet not complete. One has to check that for fault at F<sub>2</sub>, R<sub>1</sub> backs up R<sub>4</sub> with these settings calculated.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">PSM of R<sub>4&nbsp;</sub>for fault at F<sub>2</sub>&nbsp;</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">&nbsp;<span class=\"math-tex\">\\(=\\frac{5539}{1.25\\times1000\\times0.4}\\)</span></span></p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">=&nbsp; 11.078.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\)</span>&nbsp;Top of&nbsp;R<sub>4&nbsp;</sub></span></p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(=\\frac{3}{log_{10}11.078}\\times 0.1\\)</span></span></p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">= 0.2872 sec.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">PSM of R<sub>1&nbsp;</sub><span class=\"math-tex\">\\(= \\frac{1910}{1.25\\times1500\\times 0.4}\\)</span></span></p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; = 2.55.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\)</span>&nbsp;Top of&nbsp;R<sub>1&nbsp;</sub>=&nbsp;<span class=\"math-tex\">\\(\\frac{3}{log_{10}2.55}\\times 0.1\\)</span></span></p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; = 0.7379 sec.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">Top of R<sub>1</sub> &ndash; Top of R<sub>4</sub> = 0.4507 sec, which is more than minimum discrimination time margin 0.25 sec. Thus, the setting exercise is through just in first iteration. But in certain networks, more than one iteration is required. This means that if the difference calculated above is less than 0.25 sec, TMS of R<sub>1</sub> will be required to be changed to 0.15, which will change TMS of R<sub>4</sub> also. Thus, after more than one iteration, one will arrive at optimal setting.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">In this example TMS of R<sub>1</sub>/R<sub>2</sub> = 0.1 and TMS of R<sub>3</sub>/R<sub>4</sub> = 0.1.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<ol start=\"6\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Calculation of Plug-Settings of Ground Relays: We start with plug-setting of all ground relays R<sub>1</sub> to R<sub>4</sub> as 10 %.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Calculation of Time Settings of Ground Relays: TMS of R<sub>1</sub> = 0.1. Fault current = 7933 amp.</span></p>\n	</li>\n</ol>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">Secondary equivalent of this current = 5.28 amp. Therefore, current through the ground relay is equal to 5.13 amp.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\)</span>&nbsp;PSM of R<sub>1&nbsp;</sub><span class=\"math-tex\">\\(=\\frac{5.13}{0.1}\\)</span></span></p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; = 51.3.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\)</span>&nbsp;Top of&nbsp;R<sub>1&nbsp;</sub><span class=\"math-tex\">\\(=\\frac{3}{log_{10}20}\\times 0.1\\)</span></span></p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; = 0.23 sec.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">Therefore, Top of R<sub>4</sub> = 0.48 sec. </span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">PSM of R<sub>4</sub> &nbsp;<span class=\"math-tex\">\\(=\\frac{\\frac{1633}{1000}-0.15}{0.1}\\)</span></span></p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;= 14.83.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\"><span class=\"math-tex\">\\(\\dot{.\\hspace{0.095in}.}\\)</span>&nbsp;TMS of&nbsp;R<sub>4&nbsp;</sub><span class=\"math-tex\">\\(= \\frac{0.48\\times log_{10}14.83}{3}\\)</span></span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">TMS of R<sub>4</sub> = 0.1873, hence 0.2 is selected. But R<sub>1</sub> should back-up R<sub>4</sub>.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">PSM of R<sub>4</sub> for fault current 6059 amp (for fault at F<sub>2</sub>) = 59.09. Top of R<sub>4</sub> = 0.4611 sec.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">PSM of R<sub>1</sub> for fault at F<sub>2</sub> = 12.42. Top of R<sub>1</sub> = 0.274 sec. Hence, R<sub>1</sub> does not back-up R<sub>4</sub>. Further iteration will improve the situation. Finally, if TMS of R<sub>1</sub> is adjusted at 0.85 and TMS of R<sub>4</sub> at 0.9,</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">Top of R<sub>1</sub> for fault at F<sub>1</sub> = 1.9599 sec and Top of R<sub>4</sub> for same fault location = 2.3 sec, (discrimination time margin = 0.34 sec). For fault at F<sub>2</sub>, Top of R<sub>4</sub> = 2.075 sec and Top of R<sub>1</sub> for same fault location will be 2.33 sec, (discrimination time margin = 0.255 sec). Thus, we have achieved the result. But, yet if P. S. of R<sub>4</sub>/R<sub>3</sub> is adjusted at 10 % and P. S. of R<sub>1</sub>/R<sub>2</sub> at 15 %, the faster operating time is possible, yet maintaining the selectivity.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">Plug-Setting of R<sub>1</sub>/R<sub>2</sub> = 15 %. Plug-Setting of R<sub>3</sub>/R<sub>4</sub> = 10 %. TMS of R<sub>1</sub>/R<sub>2 </sub>= 0.5. </span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">TMS of R<sub>3</sub>/R<sub>4</sub> = 0.55. Top of R<sub>1</sub> for F<sub>1</sub> = 1.153 sec. Top of R<sub>4</sub> for same fault location = 1.408 sec.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">Discrimination time margin is maintained at 0.255 sec. For fault at F<sub>2</sub>, Top of R<sub>4</sub> = 1.268 sec.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\"><span style=\"font-size:14px\">Top of R<sub>1</sub> = 1.633 sec. Discrimination margin = 0.365 sec. It can be appreciated that the relays have operated faster by 0.8 sec by this change in settings. Yet, by trying different plug-settings and time settings of these four relays, the settings can be optimized. But right now, we stop here.</span></p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:24px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.13: Summary of Relay Settings of Example 5</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Relay</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">P. S. of Phase Relay in % of 1 Amp</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">TMS of Phase Relay</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">P. S. of Ground Relay in % of 1 Amp</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">TMS of Ground Relay</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>1</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">125</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.1</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">15</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.5</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>2</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">125</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.1</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">15</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.5</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>3</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">125</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.1</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">10</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.55</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">R<sub>4</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">125</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.1</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">10</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:120px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.55</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p>&nbsp;</p>\n\n<p>&nbsp;</p>\n\n<p>&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:24px; text-align:justify\">&nbsp;</p>','','1','7.3.1',NULL,'1','2','1','0','1','2021-08-19 13:26:54','2021-08-19 18:56:54'),(2476,101,'<p>7.4 Specifications of Overcurrent and Earth-fault Relays for purchasing the relays</p>','','single','html','<p style=\"text-align:justify\"><span style=\"font-size:14px\">The specification heads are written as follows and the usually available specification description is also given as made available by renowned relay manufacturers. </span></p>\n\n<ol>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Rated Current (I<sub>n</sub>): 1 amp or 5 amp.</span></p>\n	</li>\n</ol>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<ol start=\"2\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Thermal Withstand Capability:</span></p>\n	</li>\n</ol>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">Continuous: 400 % of rated current.</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">For 1 sec: 100 times the rated current.</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<ol start=\"3\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Dynamic Current Withstand: 250 times the rated current (half wave value).</span></p>\n	</li>\n</ol>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<ol start=\"4\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Burden: 50 millivolt-amp.</span></p>\n	</li>\n</ol>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<ol start=\"5\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Rated Frequency: 50 Hz or 60 Hz.</span></p>\n	</li>\n</ol>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">???????</span></p>\n\n<ol start=\"6\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Setting Ranges:</span></p>\n	</li>\n</ol>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">???????</span></p>\n\n<ol start=\"1\" style=\"list-style-type:lower-roman\">\n	<li style=\"text-align:justify\"><span style=\"font-size:14px\">Plug-Setting or Sensitivity Threshold or Start Value or Pick-up Value:</span></li>\n</ol>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">???????</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Phase Overcurrent Units: 0.05-5 times I<sub>n</sub> in steps of 0.01.</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Ground Overcurrent Units: 0.01-5 times I<sub>n</sub> in steps of 0.005.</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; I&gt;&gt; Setting Range: 0.1-40 times I<sub>n</sub> in steps of 0.01.</span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;I&gt;&gt;&gt; Setting Range: 1-40 times I<sub>n</sub> in steps of 0.01.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<ol>\n	<li style=\"list-style-type:none\">\n	<ol>\n		<li style=\"list-style-type:none\">\n		<ol start=\"2\" style=\"list-style-type:lower-roman\">\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">Start Value Multiplier: 0.8-10 in steps of 0.1.</span></p>\n			</li>\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">TMS (Time Multiplier Setting): 0.05-15 in steps of 0.05 (for IDMT curves)</span></p>\n			</li>\n		</ol>\n		</li>\n	</ol>\n	</li>\n</ol>\n\n<p style=\"margin-left:72px; text-align:justify\"><span style=\"font-size:14px\">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Operate Delay Time: 40 milli seconds-200 seconds in steps of 10 milliseconds.</span></p>\n\n<p style=\"margin-left:72px; text-align:justify\"><span style=\"font-size:14px\">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;This is for definite time overcurrent units.</span></p>\n\n<ol>\n	<li style=\"list-style-type:none\">\n	<ol>\n		<li style=\"list-style-type:none\">\n		<ol start=\"4\" style=\"list-style-type:lower-roman\">\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">Operating Curve Types:</span></p>\n			</li>\n		</ol>\n		</li>\n	</ol>\n	</li>\n</ol>\n\n<ul>\n	<li style=\"list-style-type:none\">\n	<ul>\n		<li style=\"list-style-type:none\">\n		<ul style=\"list-style-type:square\">\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">Normal Inverse.</span></p>\n			</li>\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">Very Inverse.</span></p>\n			</li>\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">Extremely Inverse</span></p>\n			</li>\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">Moderately Inverse.</span></p>\n			</li>\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">Definite Time.</span></p>\n			</li>\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">Long Time Inverse.</span></p>\n			</li>\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">Programmable Characteristic.</span></p>\n			</li>\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">Rarely Inverse</span></p>\n			</li>\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">RXIDG Type Inverse.</span></p>\n			</li>\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">I squared t type characteristic.</span></p>\n			</li>\n		</ul>\n		</li>\n	</ul>\n	</li>\n</ul>\n\n<p style=\"margin-left:96px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:96px; text-align:justify\"><span style=\"font-size:14px\">Some of these curves are as per IEC standard, some others are as per ANSI standard whereas some of them are as per IEEE standard.</span></p>\n\n<ol start=\"6\">\n	<li style=\"list-style-type:none\">\n	<ol>\n		<li style=\"list-style-type:none\">\n		<ol start=\"5\" style=\"list-style-type:lower-roman\">\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">Resetting Time: 0-60 sec in steps of 1 millisecond.</span></p>\n			</li>\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">Definite Minimum Operating Time for IDMT Relays: 20 milliseconds-60 sec in steps of 1 millisecond.</span></p>\n			</li>\n		</ol>\n		</li>\n	</ol>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Accuracy: Class 7.5 as per IS 3231.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Setting Ranges of Directional Unit:</span></p>\n\n	<ol>\n		<li style=\"list-style-type:none\">\n		<ol style=\"list-style-type:lower-roman\">\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">Characteristic Angle: - 179<sup>0</sup> to + 180<sup>0</sup> in steps of 1<sup>0</sup>.</span></p>\n			</li>\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">Polarizing Quantity: Usually cross polarization.</span></p>\n			</li>\n		</ol>\n		</li>\n	</ol>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Output Contact Rating (Binary Outputs):</span></p>\n	</li>\n</ol>\n\n<ol style=\"list-style-type:lower-alpha\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Tripping Contacts:</span></p>\n	</li>\n</ol>\n\n<ol style=\"list-style-type:lower-roman\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Rated Voltage: 250 V dc/ac.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Continuous Carry: 5 amp.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Make and carry for 0.5 sec: 30 amp.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Make and carry for 3 sec: 15 amp.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Breaking Capacity: 5 amp.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Contact Material: AgCdO<sub>2</sub>.</span></p>\n	</li>\n</ol>\n\n<ol start=\"2\" style=\"list-style-type:lower-alpha\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Signaling Contacts: </span></p>\n	</li>\n</ol>\n\n<ol style=\"list-style-type:lower-roman\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Rated Voltage: 250 V dc/ac.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Continuous Carry: 5 amp.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Make and carry for 0.5 sec: 10 amp.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Make and carry for 3 sec: 8 amp.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Breaking Capacity: 1 amp.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Contact Material: AgCdO<sub>2</sub>.</span></p>\n	</li>\n</ol>\n\n<ol start=\"10\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Binary Inputs: User can ask as per requirement. As many as 16 binary inputs are provided by manufacturers. These binary inputs can be used for many purposes such as blocking certain protection function, remote reset, changing setting group etc. Control voltage level is usually 110/220 V d. c.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Power Supply: 80-265 V ac/dc.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Tests:</span></p>\n	</li>\n</ol>\n\n<ol style=\"list-style-type:lower-roman\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Dielectric Tests:</span></p>\n	</li>\n</ol>\n\n<ol style=\"list-style-type:lower-alpha\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Power frequency overvoltage withstand test (IEC 255-5): 2 kV for 1 minute.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Impulse withstand test (IEC 255-5): 5 kV, 1.2/50 microsecond.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Insulation Resistance (IEC 255-5): More than 100 Megaohms at 500 V d. c.</span></p>\n	</li>\n</ol>\n\n<ol start=\"2\" style=\"list-style-type:lower-roman\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Disturbance Tests:</span></p>\n	</li>\n</ol>\n\n<ol style=\"list-style-type:lower-alpha\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">High frequency interference test.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Electrostatic discharge test.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Electromagnetic field test.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Magnetic field test.</span></p>\n	</li>\n</ol>\n\n<ol start=\"3\" style=\"list-style-type:lower-roman\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Mechanical Tests:</span></p>\n	</li>\n</ol>\n\n<ol style=\"list-style-type:lower-alpha\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Seismic Tests.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Vibration Test.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Shock Test.</span></p>\n	</li>\n</ol>\n\n<ol start=\"13\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Environmental Conditions:</span></p>\n	</li>\n</ol>\n\n<ol style=\"list-style-type:lower-roman\">\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Specified Ambient Service Temperature Range: -10 to + 55<sup>0</sup> C.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Transport and storage Temperature range: - 40 to + 70<sup>0</sup> C.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Enclosure Protection according to IEC 529, when the relay is panel mounted: IP 54.</span></p>\n	</li>\n</ol>','','1','7.4','Specifications of Overcurrent and Earth-fault Relays for purchasing the relays','1','2','1','0','1','2021-07-06 18:41:32','2021-11-03 16:23:38'),(2477,101,'<p>7.5 Facilities Provided in Modern Numerical Overcurrent and Earth-fault Relays</p>','','single','html','<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>Following are the facilities provided in numerical overcurrent and Earth-fault relays manufactured by renowned manufacturers.</strong></span></p>','','1','7.5','Facilities Provided in Modern Numerical Overcurrent and Earth-fault Relays','1','2','1','0','1','2021-08-18 05:01:04','2021-11-03 16:26:30'),(2478,101,'7.5.1 Self Diagnostics','','single','html','<p style=\"text-align:justify\"><span style=\"font-size:14px\">There is a facility of testing the hardware and software of the relay by a program. There is no need to test the relay periodically. If there is any fault within the relay, it will be announced on the display panel so that the rectifying actions can be taken. This feature increases the reliability of the relay and also the availability of the power system.</span></p>','','1','7.5.1',NULL,'1','2','1','0','1','2021-07-14 05:59:40','2021-07-14 11:29:40'),(2479,101,'7.5.2 Availability of many mathematical functions and logics','','single','html','<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\"><strong>Differentiation:</strong> We have seen the application of differentiation in reducing the transient overreach of instantaneous overcurrent relay. Other applications can also be there.</span></p>\n	</li>\n</ul>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\"><strong>Integration.</strong></span></p>\n	</li>\n</ul>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>???????</strong></span></p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\"><strong>Extracting negative sequence and zero sequence currents from line currents:</strong> NPS (Negative Phase Sequence) current protection (i.e., unbalanced current protection) feature can be added in the overcurrent relay using this extraction technique. Once zero sequence current is available, it can be fed to a ground overcurrent relay and no special connections (residual connection of three line CTs, ground relay across neutral CT or use of core balance CT) are required for ground overcurrent relay.</span></p>\n	</li>\n</ul>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">???????</span></p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\"><strong>Harmonic Analysis or Filtering Harmonics:</strong> Certain relays are required to be sensitive to only fundamentals. Whereas, in certain cases 2<sup>nd</sup>, 3<sup>rd</sup> or other harmonics are required to be fetched from distorted current waveshape.</span></p>\n	</li>\n</ul>','','1','7.5.2',NULL,'1','2','1','0','1','2021-07-07 09:17:20','2021-07-07 09:17:20'),(2480,101,'7.5.3 Fiber-optic Communication Between Relays','','single','html','<p style=\"text-align:justify\"><span style=\"font-size:14px\">As this communication is established in modern numerical relays, substation automation and smart grid have become possible. The communication between two coordinating relays result in very fast operating times of the relays yet maintaining the selectivity.</span></p>','','1','7.5.3',NULL,'1','2','1','0','1','2021-07-07 09:19:42','2021-07-07 09:19:42'),(2481,101,'7.5.4 Group Settings Using Binary Inputs','','single','html','<p style=\"text-align:justify\"><span style=\"font-size:14px\">There are more than one setting groups in modern numerical relays. As many as six groups are available in the relays manufactured by renowned relay manufacturers. This change in setting as per requirement makes the relay practically adaptive to dynamic nature of power system. Also, relaying system offers much better protection and more sensitive and faster protection. Some case studies are discussed as follows to understand the above statement.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256301001625630100.jpg\" style=\"height:816px; width:800px\" /></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256301601625630160.jpg\" style=\"height:523px; width:800px\" /></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\"><strong><u>Varying Generating Conditions:</u></strong> Power system is not static. It is dynamic. The normal power flow and fault currents are changing based on system conditions. The relay setting is required to adapt with this change in power system conditions. The conventional electromechanical or static relays were not capable to offer multiple groups of settings. Numerical relay offers these multiple groups of settings. One such dynamism of power system is varying generating conditions as shown in 7.30(a). Generating conditions vary based on variations of load as per load curve. If one or more generators are required to be tripped as per reduced load demand, the normal rated current flow through the transmission line varies. Also, the fault current is variable based on number of generators connected to the bus. Hence, plug-setting and time setting of overcurrent relay R are the functions of generating conditions. These can be changed accordingly as multiple sets are available in numerical relay. In earlier days, when this facility was not available, the plug-setting (only one setting value was available) was decided based on maximum possible power flow. Hence, during less power flow, say at night, the relay was less sensitive. Also, during day hours, when all generators are ON, Z<sub>s</sub>/Z<sub>l</sub> ratio is small because Z<sub>s</sub> is small. Therefore, relay R can be normal inverse overcurrent relay. But during night hours, when two (or probably 3) generators are tripped, Z<sub>s</sub> is large resulting in Z<sub>s</sub>/Z<sub>l</sub> ratio more than or equal to 2, necessitating relay R to be a very inverse relay. This dynamic change could not be done in earlier relays. But with the advent of numerical relays this is possible because in first setting group, it behaves as normal inverse relay and in second setting group, it will change its role as very inverse relay. This dynamic change can be automatic also through the binary input, if binary input is configured for change of setting group. As shown in figure 7.30(b), when any of the generator trips, the relevant breaker (say CB<sub>1</sub>) will trip. The NC auxiliary switch of that breaker can be wired in control circuit to extend 220 V D. C. to binary input to change the setting group. Thus, at different hours, the relay setting changes, increasing the relay sensitivity and faster protection. Thereby, the protection is better and more efficient. No doubt, this case study assumes that the generating plant is gas turbine plant or diesel power plant (or any other which can be switched OFF and ON fast). The thermal power plant or nuclear power plant cannot be switched OFF or ON fast.</span></p>\n	</li>\n</ul>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256302031625630203.jpg\" style=\"height:495px; width:800px\" /></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256302351625630235.jpg\" style=\"height:340px; width:800px\" /></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\"><strong><u>Parallel Feeder Protection:</u></strong> We have already discussed that, in case of parallel feeder fed from one end, relays R<sub>3</sub> and R<sub>4</sub> are directional overcurrent relays with operative direction as shown by arrowheads in the figure 7.31(a). Plug-setting of relays R<sub>1</sub>/R<sub>2</sub> shall be based on one-line contingency, i.e., 100 % of 1 amp with the details given in figure 7.31(a). TMS is to be decided based on highest fault current, i.e., both the feeders in circuit. But when both the lines are in operation, the load current per line is 500 amp and hence, the relay sensitivity is less and as the PSM will be lower, time of operation of the relay will be more. This was the status when conventional relays were used. If numerical relays are installed and commissioned, the two sets of plug-setting can be set, one with both feeders ON and second with one of the feeders tripping due to fault. That means 50 % in first case and 100 % in second case. Consequently, there will be two sets of TMS as well. The setting of relays R<sub>3</sub>/R<sub>4</sub> will also be, accordingly, in two groups. The change in group can be automatic if the change is routed through binary input configuration as suggested by figure 7.31(b).</span></p>\n	</li>\n</ul>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">???????</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256302781625630278.jpg\" style=\"height:728px; width:800px\" /></span></p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">???????</span></p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\"><u>S<strong>ingle Bus Scheme with Sectionalizing Breaker</strong>:</u> In this case, the settings of relays R<sub>1</sub>/R<sub>2</sub> are the functions of status of the sectionalizing breaker, i.e., whether it is ON or OFF. The normal current flow will be different in both cases and fault current will also be different as when the sectionalizing breaker is ON, two incomers I<sub>1</sub> and I<sub>2</sub> shown in figure 7.32 are in parallel, but with sectionalizing breaker OFF, they are not in parallel. The fault current in first case will be more than that in the other case. Hence, there will be two groups of settings (P. S. and TMS) for relays R<sub>1</sub>/R<sub>2</sub>.</span></p>\n	</li>\n</ul>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">???????</span></p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\"><strong><u>Application of Adaptive Relaying in Ring Network:</u></strong> </span></p>\n	</li>\n</ul>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256304321625630432.jpg\" style=\"height:575px; width:800px\" /></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<ul>\n	<li style=\"text-align: justify;\">\n	<p><span style=\"font-size:14px\">Referring to figure 7.33, there are four different conditions of the network:</span></p>\n	</li>\n</ul>\n\n<ol>\n	<li style=\"list-style-type:none\">\n	<ol>\n		<li style=\"list-style-type:none\">\n		<ol>\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">Lines L<sub>1</sub>, L<sub>2</sub> and L<sub>3</sub> are in operation.</span></p>\n			</li>\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">Line L<sub>1</sub> is out of operation due to forced outage. But lines L<sub>2</sub> and L<sub>3</sub> are in operation.</span></p>\n			</li>\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">Similarly, L<sub>3</sub> is not in operation but L<sub>1</sub>-L<sub>2</sub> are in operation.</span></p>\n			</li>\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">L<sub>2</sub> is tripped, L<sub>1</sub>-L<sub>3</sub> working.</span></p>\n			</li>\n		</ol>\n		</li>\n	</ol>\n	</li>\n</ol>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">The power flow in all the three lines will be different in these four cases and hence, we shall use four groups of settings available in relays. We have yet not considered forced out ages of generators of the system. The system behaviour will be very dynamic and there will be many combinations of relay settings required. All relays R<sub>1</sub> to R<sub>6</sub> are required to be properly configured to be set for different setting groups as per requirement.</span></p>','','1','7.5.4',NULL,'1','2','1','0','1','2021-07-07 09:32:53','2021-07-07 09:32:53'),(2482,101,'7.5.6  Metering, Control and Protection','','single','html','<p style=\"text-align:justify\"><span style=\"font-size:14px\">The relay offers much better, fast, sensitive, efficient and reliable protection as we are discussing in this section. But beyond that it offers metering and control facilities also.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Benefits of Metering:</span></p>\n\n	<ol>\n		<li style=\"list-style-type:none\">\n		<ol style=\"list-style-type:lower-roman\">\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">Metering of parameters such as current, voltage, power, power factor, MVA, MVAR, MWh, frequency, negative sequence current, zero sequence current etc. No separate meters are required on the panel, hence, saving of panel space.</span></p>\n			</li>\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">No separate CTs are required for meters.</span></p>\n			</li>\n		</ol>\n		</li>\n	</ol>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Benefits of Control Functions:</span></p>\n\n	<ol>\n		<li style=\"list-style-type:none\">\n		<ol style=\"list-style-type:lower-roman\">\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">ON/OFF control of breaker.</span></p>\n			</li>\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">Trip Circuit Supervision: This will be discussed later.</span></p>\n			</li>\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">Signaling Facilities.</span></p>\n			</li>\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">Blocking of Protection Function as required: This will be discussed later.</span></p>\n			</li>\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">Condition Monitoring of Circuit Breakers: Will be discussed later.</span></p>\n			</li>\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">Interlocks and Logic Functions: Will be discussed later.</span></p>\n			</li>\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">Circuit Breaker Failure Protection: Will be discussed later.</span></p>\n			</li>\n			<li style=\"text-align:justify\">\n			<p><span style=\"font-size:14px\">Switch-On-To-Fault (SOTF) Feature: Will be discussed later.</span></p>\n			</li>\n		</ol>\n		</li>\n	</ol>\n	</li>\n</ul>','','1','7.5.6',NULL,'1','2','1','0','1','2021-08-18 09:49:01','2021-08-18 15:19:01'),(2483,101,'7.5.7 Interlocking Between Circuit breaker, isolator and Earthing Switch using Logic Gates','','single','html','<p style=\"text-align:justify\"><span style=\"font-size:14px\">Logic gate functions such as AND, OR, NOR, NAND are in-built in the relay architecture. The interlocking between C. B., isolators and earthing switch can be configured in the relay programing and no separate interlocking mechanism (electrical or mechanical) is required. </span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Relay consists of different soft blocks like three phase overcurrent, overvoltage, undervoltage, circuit breaker failure function etc. The inputs to these blocks are three line currents, three line voltages, block input etc. The outputs are usually start and operate outputs. If an overcurrent relay is required to be monitored by an undervoltage unit, operate outputs of overcurrent unit and an undervoltage unit are routed to an AND logic function block, the output of which is soft-connected to a final output relay.</span></p>','','1','7.5.7',NULL,'1','2','1','0','1','2021-08-18 09:53:31','2021-08-18 15:23:31'),(2484,101,'7.5.8 Trip Circuit Supervision','','single','html','<p style=\"text-align:justify\"><span style=\"font-size:14px\">Separate trip circuit supervision relays are not required as a numerical relay is equipped with in-built trip circuit supervision facility which continuously monitors the integrity of trip coil of a breaker.</span></p>','','1','7.5.8',NULL,'1','2','1','0','1','2021-08-18 09:53:56','2021-08-18 15:23:56'),(2485,101,'7.5.9 Circuit Breaker Failure Protection (CBFP)','','single','html','<p style=\"text-align:justify\"><span style=\"font-size:14px\">The conventional relays were giving trip signal to a breaker. But, if the trip coil of the breaker is open or if there is some trouble with operating mechanism of the breaker or the air (or gas) pressure is insufficient to operate the breaker, the breaker will not trip and hence the fault will not be cleared. There was no facility in conventional relays to monitor the failure of the breaker. But, in numerical relays such circuit breaker failure function is available. Referring to figure 7.34(a), there is a fault at F. Relay R<sub>2</sub> senses the fault and operates as per its characteristic. R<sub>2</sub> gives signal to the breaker CB<sub>2</sub>. Now, if CB<sub>2</sub> fails to trip (because of any trouble of the breaker), R<sub>2</sub> will sense this failure of the breaker CB<sub>2</sub>, it will wait for some time (CB<sub>2</sub> operate time plus some safety margin) and after expiry of this (adjustable) time, the relay R<sub>2</sub> will generate another signal which can be used to sound an alarm (informing that CB<sub>2</sub> has failed) or the same signal can be used to trip the upstream breaker CB<sub>1</sub>.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16292803141629280314.jpg\" style=\"height:598px; width:800px\" /></span></p>','','1','7.5.9',NULL,'1','2','1','0','1','2021-08-18 09:52:09','2021-08-18 15:22:09'),(2486,101,'7.5.10 Condition Monitoring of Circuit Breakers and Transformers','','single','html','<p style=\"text-align:justify\"><span style=\"font-size:14px\">When the circuit breaker opens on fault, there will be an arc struck between two contacts. The arc is quenched but there will be deposition of carbon products on the contacts. Hence, these contacts are to be periodically cleaned after certain ON-OFF functions. Spring adjustment is required to be done after certain breaks. These ON-OFF events and breaks due to fault clearing are recorded by numerical relays and a reminder generated on the front display window to let the maintenance staff know that the maintenance is due. Similar facility for transformer condition monitoring is available in these relays.</span></p>','','1','7.5.10',NULL,'1','2','1','0','1','2021-07-07 09:43:29','2021-07-07 09:43:29'),(2487,101,'7.5.11 Starting Function and Blocking Function (Reverse Interlocking) Using Binary Inputs','','single','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256314411625631441.jpg\" style=\"height:598px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256315101625631510.jpg\" style=\"height:583px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Refer figure 7.34(a). There is a fault at F. Overcurrent relay R<sub>2</sub> senses the fault and operates after (say) 0.1 sec. Overcurrent relay R<sub>1</sub> acts as a back-up and is set to operate after 0.35 sec (discrimination margin 0.25 sec as we have discussed earlier). Hence, the first disadvantage of time-graded discriminative system is the time delay. Overcurrent relay R<sub>1</sub> will operate after 0.35 second if R<sub>2</sub> fails. If there is a fault at the bus, R<sub>1</sub> will operate and breaker CB<sub>1</sub> will trip to clear the fault after 0.35 second only, not earlier. This is the second disadvantage of time grading. But this was essential with the use of conventional relays. The numerical relay on the other hand, is equipped with the facility such that this discrimination time margin can be drastically reduced. They are provided with &ldquo;start&rdquo; and &ldquo;block&rdquo; functions. The relay takes sample of the current every 1 millisecond (typical sampling time). If it uses 3-sample technique, it will sense the fault within 3 milliseconds (more accurate are half and full cycle Fourier algorithms in which case fault will be diagnosed after half a cycle and one cycle respectively). Thus, fault is detected after one cycle (maximum), i.e., 20 milliseconds. Hence, for fault at F, the relay R<sub>2</sub> will sense the fault after 20 milliseconds (it is going to operate after 0.1 sec, i.e., 100 milliseconds). Therefore after 20 milliseconds, the start output is excited (logic state 1). This output can be routed to a signaling output relay (which is a d. c. operated attracted armature analog relay). The contact of this signal relay R<sub>2</sub>-start [figure 7.34(b)] can be used to block operation of relay R<sub>1</sub> through binary input. Thus, if R<sub>2</sub> senses the fault, operation of R<sub>1</sub> is blocked. This is also known as reverse interlocking. Therefore, now, a time delay for the operation of an auxiliary tripping relay (about 40 milliseconds) is enough as a discrimination margin between R<sub>1</sub> and R<sub>2</sub>. R<sub>1</sub> will, in this case, be set to operate after 0.14 sec. If there is a bus fault now, Relay R<sub>1</sub> will operate after 0.14 sec only, thus very fast operation. Thus, there is a revolutionary change in the rules of setting and the protection offered is very fast and hence probably no damage to the equipment as against possibility of certain damages to electrical equipment due to slow protective system offered by earlier conventional relays.</span></p>','','1','7.5.11',NULL,'1','2','1','0','1','2021-07-07 09:48:52','2021-07-07 09:48:52'),(2488,101,'7.5.12 Auto-multiplying (facility of start value multiplier mentioned in Specifications of relays) the setting during transient conditions','','single','html','<p style=\"text-align:justify\"><span style=\"font-size:14px\">When the power transformer is energized, the worst magnetizing inrush current can be as large as 10 times the CMR of transformer primary. This current exponentially reduces to a normal value after 15-30 cycles depending upon L/R ratio. Hence, the setting of instantaneous overcurrent unit has to be set beyond this inrush value. If there is an internal fault within the transformer which can be 6-8 times the CMR of the transformer, it will be taken care of by time delayed unit only. The internal faults are dangerous and can shatter the transformer. A numerical relay offers a facility in which it discriminates between inrush function and fault function. Inrush current rises from zero to 10 times the rated current of transformer. It also contains many harmonic components. Thus, it is distorted. Also, it is exponentially decaying. This behaviour of current is analyzed and tagged as inrush function. Whereas, fault current rises from about rated current (1 time the CMR) to 5-8 times CMR. The waveshape is also different. This is tagged as fault function. If it is an inrush function, the high-set (I &gt;&gt; and/or I &gt;&gt;&gt;) setting is temporarily multiplied automatically by n (adjustable) times the set value till the inrush continues. Once inrush dies down, the instantaneous setting resumes to original set value automatically. In case of fault function, this multiplication does not take place. This facility allows the instantaneous setting to be decided at a value less than the possible inrush value. The similar is the case of motor starting current which is of the order of 6 times CMR of motor. Starting time varies from 6 seconds to as large as 30 seconds in case of large inertia motors like PA fan motor in thermal power plant. In this case also, it is possible to set instantaneous unit setting at a value less than starting current if we use numerical relay.</span></p>','','1','7.5.12',NULL,'1','2','1','0','1','2021-07-07 09:50:09','2021-07-07 09:50:09'),(2489,101,'7.5.13 Switch-On-To-Fault (SOTF) facility','','single','html','<p style=\"text-align:justify\"><span style=\"font-size:14px\">If the circuit breaker is switched ON when the fault is already existing, this facility can be used. If such a situation occurs, the numerical relay will issue a trip command instantaneously bypassing all delays. This feature is useful in two important applications.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">In directional overcurrent relay, we have seen that if the breaker is inadvertently made ON when the earthing switch is ON (0.2 % probability), the directional overcurrent relay fails to operate even though the fault is in operative direction. This is because all line and phase voltages are zero at the relaying point and hence torque developed by the relay is zero. This SOTF facility, in this case, will sense the fault and will issue a trip command instantaneously.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">If the breaker is switched ON when the earthing switch at the other end of the line is ON (there is no interlock between the breaker at one end of the line and an earthing switch at the other end of the line) by mistake, this is closing on to fault. As the fault is at the end of the line, the in-built instantaneous unit of the overcurrent relay cannot operate (as it is set for a triple line fault at 80 % length of the line). The time delayed unit will sense this fault and hence fault will be cleared after the set time delay. This was the case when conventional relays were used. But, with this SOTF facility in numerical relays, this situation is sensed as closing on to fault and hence the relay will issue an instantaneous trip command.</span></p>\n	</li>\n</ul>','','1','7.5.13',NULL,'1','2','1','0','1','2021-07-07 09:51:36','2021-07-07 09:51:36'),(2490,101,'7.5.14 Load-Shedding Using df/dt, dv/dt Functions','','single','html','<p style=\"text-align:justify\"><span style=\"font-size:14px\">When power demand is more than the generation and spinning reserve is not available, the frequency and voltage will drop to cope with the increased load demand. Reduction in frequency is harmful for generators as the steam will condense in last stages of LP turbine damaging them (in thermal power plant). Even if the frequency drops by very small percentage of normal frequency, the life expectancy of steam turbines is reduced. The good power quality demands that there should be no frequency variation, no voltage variation (or extremely little variation) and THD (Total Harmonic Distortion) not greater than 3 %. The numerical relay connected for protection of 11 kV feeder measures df/dt and dv/dt and trips the 11 kV line if df/dt value is more than certain pre-set value. Thus, tripping is established even before the frequency drops below the value that can damage the generator unit. This is known as automatic load-shedding.</span></p>','','1','7.5.14',NULL,'1','2','1','0','1','2021-07-07 09:54:10','2021-07-07 09:54:10'),(2491,101,'7.5.15 Fast Bus Transfer','','single','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256319661625631966.jpg\" style=\"height:728px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">In a single bus system with a bus sectionalizing breaker, as shown in figure 7.32, if incomers I<sub>1</sub> and I<sub>2</sub> are fed from two different sources, when B<sub>1</sub> or B<sub>2</sub> is made ON (sectionalizing breaker is ON), the synchronizing conditions are required to be checked. This means that (a) bus voltage and incomer (one that is being connected to the bus) voltage must be same, (b) bus frequency and incomer frequency must be same and (c) the instantaneous value of the voltage wave of bus and that of the incomer must be same. These conditions are checked by the numerical overcurrent relay (connected in the incomer) very fast and the concerned breaker is closed at the correct instant. This facility is known as Fast Bus Transfer.</span></p>','','1','7.5.15',NULL,'1','2','1','0','1','2021-07-07 09:56:20','2021-07-07 09:56:20'),(2492,101,'7.5.16 Voltage Memory of Pre-fault Voltage in Case of Directional Relays','','single','html','<p style=\"text-align:justify\"><span style=\"font-size:14px\">We have already discussed that some minimum voltage is required for the operation of the directional relay. The numerical directional relay provides the facility of voltage memory in such a case where voltage available to relay is small. The relay measures the voltage available at relaying point and if it is less than certain pre-set value (usually 15 % of 110 V, the rated voltage), the voltage memory function is activated. The relay, in this case, uses the memorized pre-fault voltage.</span></p>','','1','7.5.16',NULL,'1','2','1','0','1','2021-07-07 10:04:02','2021-07-07 10:04:02'),(2493,101,'7.5.17 Polarity Change in Case of Directional Relay','','single','html','<p style=\"text-align:justify\"><span style=\"font-size:14px\">If polarity of CT or PT is wrongly connected, the operative direction reverses, i.e., towards the bus (rather than away from the bus as it should be). In this case, rather than physically correcting the polarity at CT/PT terminals, soft polarity changing facility is offered by the numerical relay (which is very convenient and less time consuming).</span></p>','','1','7.5.17',NULL,'1','2','1','0','1','2021-07-07 10:05:07','2021-07-07 10:05:07'),(2494,101,'The extremely inverse overcurrent relays suffer from the problem of overreach, when applied to protection of transmission lines.','','multi','single','','','1','7.1.1',NULL,'2','6','1','0','1','2021-07-07 10:09:45','2021-07-07 10:09:45'),(2495,101,'Overcurrent relays are not used for protection of extra high voltage transmission lines.','','multi','single','','','1','7.1',NULL,'2','4,6','1','0','1','2021-07-07 10:11:45','2021-07-07 10:11:45'),(2496,101,'7.1.6 Refer to the media and select an answer.','','multi','html','<p><span style=\"font-size:14px\"><strong>Very inverse overcurrent relays are used where Z<sub>s</sub>/Z<sub>l</sub> ratio is unity. </strong></span></p>','','1','7.1.6',NULL,'2','3,6','1','0','1','2021-07-13 10:57:27','2021-07-13 16:27:27'),(2497,101,'Extremely inverse overcurrent relays are used where fault current is less than the maximum load current.','','multi','single','','','1','7.1.6',NULL,'2','1,3','1','0','1','2021-07-07 10:17:08','2021-07-07 10:17:08'),(2498,101,'Ground relays can be set at P. S. equal to 150 %.','','multi','single','','','1','7.1.7',NULL,'2','3,6','1','0','1','2021-07-07 10:24:08','2021-07-07 10:24:08'),(2499,101,'7.1.1 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><span style=\"font-size:11pt\">The maximum percentage of line protected by an instantaneous overcurrent relay for&nbsp;an L-L fault is</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:11pt\">Assume that </span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<ul>\n	<li style=\"text-align:justify\"><span style=\"font-size:11pt\">transient overreach of the relay is 10 %.</span></li>\n	<li style=\"text-align:justify\"><span style=\"font-size:11pt\">Z<sub>s</sub>/Z<sub>l</sub> ratio to be unity.</span></li>\n	<li style=\"text-align:justify\"><span style=\"font-size:11pt\">Z<sub>1</sub> = Z<sub>2</sub>, for all equipment of the power system.</span></li>\n	<li style=\"text-align:justify\"><span style=\"font-size:11pt\">Z<sub>f</sub> = 0</span></li>\n</ul>\n\n<p style=\"margin-left:96px; text-align:justify\">&nbsp;</p>','','1','7.1.1',NULL,'3','6,7','1','0','1','2021-08-18 09:08:20','2021-08-18 14:38:20'),(2500,101,'7.2 Refer to the media and select an answer.','','multi','html','<p><span style=\"font-size:14px\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256346751625634675.jpg\" style=\"height:961px; width:800px\" /></span></p>\n\n<p>&nbsp;</p>\n\n<p><span style=\"font-size:14px\">In figure 7.35, R<sub>1</sub> to R<sub>10</sub> are directional or non-directional overcurrent relays as the requirement calls for. Which relays will back-up relay R<sub>2&nbsp;</sub>?</span></p>','','1','7.2',NULL,'2','4,6','1','0','1','2021-08-11 13:08:48','2021-08-11 18:38:48'),(2501,101,'In figure 7.35, R1 to R10 are directional or non-directional overcurrent relays as the requirement calls for. Which relays will back-up relay R5?','','multi','html','<p><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256341771625634177.jpg\" style=\"height:961px; width:800px\" /></p>','','1','7.2',NULL,'4','4,6','1','1','1','2021-07-07 05:15:27','2021-07-07 10:45:27'),(2502,101,'7.2 Refer to the media and select an answer.','','multi','html','<p><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256385081625638508.jpg\" style=\"height:961px; width:800px\" /></p>\n\n<p>&nbsp;</p>\n\n<p>&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>In figure 7.35, R<sub>1</sub> to R<sub>10</sub> are directional or non-directional overcurrent relays as the requirement calls for. Which relays will back-up relay R<sub>5</sub>?</strong></span></p>','','1','7.2',NULL,'4','4,6','1','0','1','2021-08-11 13:10:24','2021-08-11 18:40:24'),(2503,101,'7.2 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256389271625638927.jpg\" style=\"height:961px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>In figure 7.35, R<sub>1</sub> to R<sub>10</sub> are directional or non-directional overcurrent relays as the requirement calls for. Non-directional relays are</strong></span></p>','','1','7.2',NULL,'3','4,6','1','0','1','2021-08-11 12:57:43','2021-08-11 18:27:43'),(2504,101,'7.2.1 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256393461625639346.jpg\" style=\"height:434px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>Refer figure 7.36. P. S. of phase overcurrent relay R<sub>5</sub> shall be set at</strong></span></p>','','1','7.2.1',NULL,'4','4,6','1','0','1','2021-07-13 12:09:16','2021-07-13 17:39:16'),(2505,101,'7.2.1 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256394571625639457.jpg\" style=\"height:434px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>Refer figure 7.36. P. S. of phase relays R<sub>1</sub>/R<sub>2</sub> shall be set at</strong></span></p>','','1','7.2.1',NULL,'1','4,6','1','0','1','2021-07-13 12:10:42','2021-07-13 17:40:42'),(2506,101,'7.2.1 Refer to the media and select an answer.','','multi','html','<ol>\n</ol>\n\n<p><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256396071625639607.jpg\" style=\"height:434px; width:800px\" /></p>\n\n<p>&nbsp;</p>\n\n<p>&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>Refer figure 7.36. P. S. phase relays of R<sub>3</sub>/R<sub>4</sub> shall be set at</strong></span></p>\n\n<ol>\n</ol>','','1','7.2.1',NULL,'2','4,6','1','0','1','2021-07-13 12:13:59','2021-07-13 17:43:59'),(2507,101,'Breakers tripping “A” will be','','multi','html','<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>Refer figure 7.37 and table 7.14 below:</strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256397581625639758.jpg\" style=\"height:585px; width:800px\" /></strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:113px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.14</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:119px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Location</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:184px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Remarks</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:131px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Breakers Tripping</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:119px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">F<sub>1</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:184px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Breaker 6 did not trip.</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:131px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:119px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">F<sub>2</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:184px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus Differential Relay did not operate.</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:131px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:119px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">F<sub>3</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:184px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Overcurrent Relay at Location 12 was Taken out for Testing.</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:131px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:119px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">F<sub>4</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:184px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">--</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:131px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">D</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>','','1','7.2.1',NULL,'1','4,6,8','1','0','1','2021-07-07 12:08:59','2021-07-07 12:08:59'),(2508,101,'Referring to figure 7.37 and table 7.14, breakers “B” tripping will be','','multi','html','<ol>\n</ol>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>Refer figure 7.37 and table 7.14 below:</strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256400791625640079.jpg\" style=\"height:585px; width:800px\" /></strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:113px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.14</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:119px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Location</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:184px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Remarks</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:131px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Breakers Tripping</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:119px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">F<sub>1</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:184px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Breaker 6 did not trip.</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:131px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:119px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">F<sub>2</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:184px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus Differential Relay did not operate.</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:131px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:119px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">F<sub>3</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:184px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Overcurrent Relay at Location 12 was Taken out for Testing.</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:131px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:119px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">F<sub>4</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:184px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">--</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:131px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">D</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<ol>\n</ol>','','1','7.2.1',NULL,'2','4,6,8','1','0','1','2021-07-07 12:13:37','2021-07-07 12:13:37'),(2509,101,'Referring to figure 7.37 and table 7.14, breakers “C” tripping will be','','multi','html','<p><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256403291625640329.jpg\" style=\"height:585px; width:800px\" /></p>\n\n<p>&nbsp;</p>\n\n<p>&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:113px; width:900px\">\n	<caption>\n	<p><span style=\"font-size:18px\"><strong>Table 7.14</strong></span></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:119px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Location</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:184px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Remarks</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:131px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Breakers Tripping</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:119px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">F<sub>1</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:184px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Breaker 6 did not trip.</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:131px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:119px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">F<sub>2</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:184px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus Differential Relay did not operate.</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:131px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:119px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">F<sub>3</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:184px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Overcurrent Relay at Location 12 was Taken out for Testing.</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:131px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:119px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">F<sub>4</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:184px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">--</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:131px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">D</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>','','1','7.2.1',NULL,'4','4,6,8','1','0','1','2021-07-07 12:17:05','2021-07-07 12:17:05'),(2510,101,'Referring to figure 7.37 and table 7.14, breakers “D” tripping will be','','multi','html','<p><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256406051625640605.jpg\" style=\"height:585px; width:800px\" /></p>\n\n<p>&nbsp;</p>\n\n<p>&nbsp;</p>\n\n<p>&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:113px; width:900px\">\n	<caption>\n	<p><span style=\"font-size:18px\">Table 7.14</span></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:119px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Location</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:184px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Remarks</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:131px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Breakers Tripping</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:119px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">F<sub>1</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:184px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Breaker 6 did not trip.</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:131px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:119px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">F<sub>2</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:184px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus Differential Relay did not operate.</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:131px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:119px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">F<sub>3</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:184px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Overcurrent Relay at Location 12 was Taken out for Testing.</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:131px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:119px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">F<sub>4</sub></span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:184px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">--</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:131px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">D</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>','','1','7.2.1',NULL,'3','4,6,8','1','0','1','2021-07-07 12:22:32','2021-07-07 12:22:32'),(2511,101,'7.1.6 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><span style=\"font-size:14px\">When Z<sub>s</sub>/Z<sub>l</sub> ratio is less than 2,</span></p>','','1','7.1.6',NULL,'1','3,6','1','0','1','2021-07-07 12:25:03','2021-07-07 12:25:03'),(2512,101,'The time discrimination between two coordinating overcurrent relays for back-up is decided based on','','multi','single','','','1','7.1.4',NULL,'4','1,3','1','0','1','2021-07-07 12:26:30','2021-07-07 12:26:30'),(2513,101,'The plug-setting of a ground relay is decided based on','','multi','single','','','1','7.1.7',NULL,'3','3,6','1','0','1','2021-07-07 12:28:11','2021-07-07 12:28:11'),(2514,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256461661625646166.jpg\" style=\"height:616px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.38 shows a single line diagram of a portion of a power system network. The relays R<sub>1</sub> to R<sub>7</sub> are normal inverse IDMT overcurrent relays with usual range. All four induction motors are identical with ratings as follows:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">Three-phase, 11 kV, 2000 hp, efficiency = 90 %, 0.85 pf, overload withstand = 110 % of rated current.</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">The fault currents for faults at different buses are tabulated below:</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:104px; width:900px\">\n	<caption>\n	<p><span style=\"font-size:14px\"><strong>Table 7.15: Fault Currents at Different Buses</strong></span></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Triple Line Fault in Amp</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Double Line Fault in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4860</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4208</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2754</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2385</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">10139</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">8780</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">D</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3983</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3450</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p>&nbsp;</p>\n\n<p>&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">TMS of R<sub>7</sub> and R<sub>5</sub> are set at 0.1 and 0.3 respectively and the high-set instantaneous setting of relays R<sub>5</sub> and R<sub>3</sub> are set at 700 % and 2000 % of the relay rating respectively. Allow 10 % overload while deciding plug-setting of all relays. Relay R<sub>1</sub> is voltage-controlled overcurrent relay such that its plug-setting reduces to 40 % of set value if voltage collapses below 70 % of rated voltage. Assume</span></p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">1 hp = 735.5 Watts.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Instantaneous time of operation of relays = 0.06 sec.</span></p>\n	</li>\n</ul>\n\n<p>&nbsp;</p>\n\n<p><span style=\"font-size:14px\"><strong>P. S. of phase relay R<sub>7</sub> shall be set at</strong></span></p>','','1','7.1.5',NULL,'2','4,6,8','1','0','1','2021-07-13 10:52:43','2021-07-13 16:22:43'),(2515,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256465791625646579.jpg\" style=\"height:616px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.38 shows a single line diagram of a portion of a power system network. The relays R<sub>1</sub> to R<sub>7</sub> are normal inverse IDMT overcurrent relays with usual range. All four induction motors are identical with ratings as follows:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Three-phase, 11 kV, 2000 hp, efficiency = 90 %, 0.85 pf, overload withstand = 110 % of rated current.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">The fault currents for faults at different buses are tabulated below:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:104px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.15: Fault Currents at Different Buses</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Triple Line Fault in Amp</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Double Line Fault in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4860</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4208</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2754</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2385</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">10139</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">8780</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">D</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3983</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3450</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p>&nbsp;</p>\n\n<p>&nbsp;</p>\n\n<p>&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">TMS of R<sub>7</sub> and R<sub>5</sub> are set at 0.1 and 0.3 respectively and the high-set instantaneous setting of relays R<sub>5</sub> and R<sub>3</sub> are set at 700 % and 2000 % of the relay rating respectively. Allow 10 % overload while deciding plug-setting of all relays. Relay R<sub>1</sub> is voltage-controlled overcurrent relay such that its plug-setting reduces to 40 % of set value if voltage collapses below 70 % of rated voltage. Assume</span></p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">1 hp = 735.5 Watts.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Instantaneous time of operation of relays = 0.06 sec.</span></p>\n	</li>\n</ul>\n\n<p>&nbsp;</p>\n\n<p><span style=\"font-size:14px\"><strong>P. S. of phase relay R<sub>6</sub> shall be set at</strong></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'3','4,6,8','1','0','1','2021-07-13 05:50:40','2021-07-13 11:20:40'),(2516,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256468791625646879.jpg\" style=\"height:616px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.38 shows a single line diagram of a portion of a power system network. The relays R<sub>1</sub> to R<sub>7</sub> are normal inverse IDMT overcurrent relays with usual range. All four induction motors are identical with ratings as follows:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">Three-phase, 11 kV, 2000 hp, efficiency = 90 %, 0.85 pf, overload withstand = 110 % of rated current.</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">The fault currents for faults at different buses are tabulated below:</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:104px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.15: Fault Currents at Different Buses</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Triple Line Fault in Amp</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Double Line Fault in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4860</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4208</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2754</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2385</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">10139</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">8780</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">D</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3983</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3450</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">TMS of R<sub>7</sub> and R<sub>5</sub> are set at 0.1 and 0.3 respectively and the high-set instantaneous setting of relays R<sub>5</sub> and R<sub>3</sub> are set at 700 % and 2000 % of the relay rating respectively. Allow 10 % overload while deciding plug-setting of all relays. Relay R<sub>1</sub> is voltage-controlled overcurrent relay such that its plug-setting reduces to 40 % of set value if voltage collapses below 70 % of rated voltage. Assume</span></p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">1 hp = 735.5 Watts.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Instantaneous time of operation of relays = 0.06 sec.</span></p>\n	</li>\n</ul>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>P. S. of phase relay R<sub>5</sub> shall be set at</strong></span></p>','','1','7.1.5',NULL,'1','4,6,8','1','0','1','2021-07-13 05:52:11','2021-07-13 11:22:11'),(2517,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256471761625647176.jpg\" style=\"height:616px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.38 shows a single line diagram of a portion of a power system network. The relays R<sub>1</sub> to R<sub>7</sub> are normal inverse IDMT overcurrent relays with usual range. All four induction motors are identical with ratings as follows:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">Three-phase, 11 kV, 2000 hp, efficiency = 90 %, 0.85 pf, overload withstand = 110 % of rated current.</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">The fault currents for faults at different buses are tabulated below:</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:104px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.15: Fault Currents at Different Buses</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Triple Line Fault in Amp</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Double Line Fault in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4860</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4208</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2754</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2385</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">10139</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">8780</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">D</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3983</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3450</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">TMS of R<sub>7</sub> and R<sub>5</sub> are set at 0.1 and 0.3 respectively and the high-set instantaneous setting of relays R<sub>5</sub> and R<sub>3</sub> are set at 700 % and 2000 % of the relay rating respectively. Allow 10 % overload while deciding plug-setting of all relays. Relay R<sub>1</sub> is voltage-controlled overcurrent relay such that its plug-setting reduces to 40 % of set value if voltage collapses below 70 % of rated voltage. Assume</span></p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">1 hp = 735.5 Watts.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Instantaneous time of operation of relays = 0.06 sec.</span></p>\n	</li>\n</ul>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\"><strong>P. S. of phase relay R<sub>3</sub> shall be set at</strong></span></p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'2','4,6,8','1','0','1','2021-07-13 05:52:54','2021-07-13 11:22:54'),(2518,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256473471625647347.jpg\" style=\"height:616px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.38 shows a single line diagram of a portion of a power system network. The relays R<sub>1</sub> to R<sub>7</sub> are normal inverse IDMT overcurrent relays with usual range. All four induction motors are identical with ratings as follows:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">Three-phase, 11 kV, 2000 hp, efficiency = 90 %, 0.85 pf, overload withstand = 110 % of rated current.</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">The fault currents for faults at different buses are tabulated below:</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:104px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.15: Fault Currents at Different Buses</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Triple Line Fault in Amp</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Double Line Fault in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4860</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4208</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2754</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2385</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">10139</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">8780</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">D</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3983</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3450</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">TMS of R<sub>7</sub> and R<sub>5</sub> are set at 0.1 and 0.3 respectively and the high-set instantaneous setting of relays R<sub>5</sub> and R<sub>3</sub> are set at 700 % and 2000 % of the relay rating respectively. Allow 10 % overload while deciding plug-setting of all relays. Relay R<sub>1</sub> is voltage-controlled overcurrent relay such that its plug-setting reduces to 40 % of set value if voltage collapses below 70 % of rated voltage. Assume</span></p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">1 hp = 735.5 Watts.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Instantaneous time of operation of relays = 0.06 sec.</span></p>\n	</li>\n</ul>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>P. S. of phase relay R<sub>4 </sub>shall be set at</strong></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px\">&nbsp;</p>','','1','7.1.5',NULL,'4','4,6,8','1','0','1','2021-07-13 06:17:30','2021-07-13 11:47:30'),(2519,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256477231625647723.jpg\" style=\"height:616px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.38 shows a single line diagram of a portion of a power system network. The relays R<sub>1</sub> to R<sub>7</sub> are normal inverse IDMT overcurrent relays with usual range. All four induction motors are identical with ratings as follows:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">Three-phase, 11 kV, 2000 hp, efficiency = 90 %, 0.85 pf, overload withstand = 110 % of rated current.</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">The fault currents for faults at different buses are tabulated below:</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:104px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.15: Fault Currents at Different Buses</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Triple Line Fault in Amp</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Double Line Fault in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4860</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4208</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2754</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2385</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">10139</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">8780</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">D</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3983</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3450</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">TMS of R<sub>7</sub> and R<sub>5</sub> are set at 0.1 and 0.3 respectively and the high-set instantaneous setting of relays R<sub>5</sub> and R<sub>3</sub> are set at 700 % and 2000 % of the relay rating respectively. Allow 10 % overload while deciding plug-setting of all relays. Relay R<sub>1</sub> is voltage-controlled overcurrent relay such that its plug-setting reduces to 40 % of set value if voltage collapses below 70 % of rated voltage.</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">Assume</span></p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">1 hp = 735.5 Watts.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Instantaneous time of operation of relays = 0.06 sec.</span></p>\n	</li>\n</ul>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\"><strong>&nbsp;P. S. of phase relay R<sub>2</sub> shall be set at</strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'3','4,6,8','1','0','1','2021-07-13 06:18:07','2021-07-13 11:48:07'),(2520,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256556801625655680.jpg\" style=\"height:616px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.38 shows a single line diagram of a portion of a power system network. The relays R<sub>1</sub> to R<sub>7</sub> are normal inverse IDMT overcurrent relays with usual range. All four induction motors are identical with ratings as follows:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">Three-phase, 11 kV, 2000 hp, efficiency = 90 %, 0.85 pf, overload withstand = 110 % of rated current.</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">The fault currents for faults at different buses are tabulated below:</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:104px; width:900px\">\n	<caption>\n	<p><span style=\"font-size:18px\"><strong>Table 7.15: Fault Currents at Different Buses</strong></span></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Triple Line Fault in Amp</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Double Line Fault in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4860</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4208</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2754</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2385</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">10139</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">8780</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">D</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3983</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3450</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">TMS of R<sub>7</sub> and R<sub>5</sub> are set at 0.1 and 0.3 respectively and the high-set instantaneous setting of relays R<sub>5</sub> and R<sub>3</sub> are set at 700 % and 2000 % of the relay rating respectively. Allow 10 % overload while deciding plug-setting of all relays. Relay R<sub>1</sub> is voltage-controlled overcurrent relay such that its plug-setting reduces to 40 % of set value if voltage collapses below 70 % of rated voltage. Assume</span></p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">1 hp = 735.5 Watts.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Instantaneous time of operation of relays = 0.06 sec.</span></p>\n	</li>\n</ul>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>&nbsp;P. S. of phase relay R<sub>1</sub> shall be set at</strong></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'4','4,6,8','1','0','1','2021-07-13 06:16:38','2021-07-13 11:46:38'),(2521,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256557631625655763.jpg\" style=\"height:616px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.38 shows a single line diagram of a portion of a power system network. The relays R<sub>1</sub> to R<sub>7</sub> are normal inverse IDMT overcurrent relays with usual range. All four induction motors are identical with ratings as follows:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">Three-phase, 11 kV, 2000 hp, efficiency = 90 %, 0.85 pf, overload withstand = 110 % of rated current.</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">The fault currents for faults at different buses are tabulated below:</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:104px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.15: Fault Currents at Different Buses</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Triple Line Fault in Amp</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Double Line Fault in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4860</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4208</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2754</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2385</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">10139</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">8780</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">D</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3983</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3450</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">TMS of R<sub>7</sub> and R<sub>5</sub> are set at 0.1 and 0.3 respectively and the high-set instantaneous setting of relays R<sub>5</sub> and R<sub>3</sub> are set at 700 % and 2000 % of the relay rating respectively. Allow 10 % overload while deciding plug-setting of all relays. Relay R<sub>1</sub> is voltage-controlled overcurrent relay such that its plug-setting reduces to 40 % of set value if voltage collapses below 70 % of rated voltage. Assume</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">1 hp = 735.5 Watts.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Instantaneous time of operation of relays = 0.06 sec.</span></p>\n	</li>\n</ul>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>TMS of phase relay R<sub>6</sub> shall be set at</strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">&nbsp;</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'3','4,6,8','1','0','1','2021-07-13 06:05:36','2021-07-13 11:35:36'),(2522,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256560831625656083.jpg\" style=\"height:616px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.38 shows a single line diagram of a portion of a power system network. The relays R<sub>1</sub> to R<sub>7</sub> are normal inverse IDMT overcurrent relays with usual range. All four induction motors are identical with ratings as follows:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">Three-phase, 11 kV, 2000 hp, efficiency = 90 %, 0.85 pf, overload withstand = 110 % of rated current.</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">The fault currents for faults at different buses are tabulated below:</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:104px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.15: Fault Currents at Different Buses</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Triple Line Fault in Amp</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Double Line Fault in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4860</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4208</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2754</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2385</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">10139</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">8780</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">D</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3983</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3450</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">TMS of R<sub>7</sub> and R<sub>5</sub> are set at 0.1 and 0.3 respectively and the high-set instantaneous setting of relays R<sub>5</sub> and R<sub>3</sub> are set at 700 % and 2000 % of the relay rating respectively. Allow 10 % overload while deciding plug-setting of all relays. Relay R<sub>1</sub> is voltage-controlled overcurrent relay such that its plug-setting reduces to 40 % of set value if voltage collapses below 70 % of rated voltage. Assume</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">1 hp = 735.5 Watts.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Instantaneous time of operation of relays = 0.06 sec.</span></p>\n	</li>\n</ul>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>TMS of phase relay R<sub>3</sub> shall be set at</strong></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">&nbsp;</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'2','4,6,8','1','0','1','2021-07-13 05:49:42','2021-07-13 11:19:42'),(2523,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256563021625656302.jpg\" style=\"height:616px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.38 shows a single line diagram of a portion of a power system network. The relays R<sub>1</sub> to R<sub>7</sub> are normal inverse IDMT overcurrent relays with usual range. All four induction motors are identical with ratings as follows:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">Three-phase, 11 kV, 2000 hp, efficiency = 90 %, 0.85 pf, overload withstand = 110 % of rated current.</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">The fault currents for faults at different buses are tabulated below:</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:104px; width:900px\">\n	<caption>\n	<p><span style=\"font-size:18px\"><strong>Table 7.15: Fault Currents at Different Buses</strong></span></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Triple Line Fault in Amp</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Double Line Fault in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4860</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4208</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2754</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2385</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">10139</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">8780</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">D</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3983</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3450</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">TMS of R<sub>7</sub> and R<sub>5</sub> are set at 0.1 and 0.3 respectively and the high-set instantaneous setting of relays R<sub>5</sub> and R<sub>3</sub> are set at 700 % and 2000 % of the relay rating respectively. Allow 10 % overload while deciding plug-setting of all relays. Relay R<sub>1</sub> is voltage-controlled overcurrent relay such that its plug-setting reduces to 40 % of set value if voltage collapses below 70 % of rated voltage. Assume</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">1 hp = 735.5 Watts.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Instantaneous time of operation of relays = 0.06 sec.</span></p>\n	</li>\n</ul>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>&nbsp;TMS of phase relay R<sub>4</sub> shall be set at</strong></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'1','4,6,8','1','0','1','2021-07-13 11:36:49','2021-07-13 17:06:49'),(2524,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256579351625657935.jpg\" style=\"height:616px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.38 shows a single line diagram of a portion of a power system network. The relays R<sub>1</sub> to R<sub>7</sub> are normal inverse IDMT overcurrent relays with usual range. All four induction motors are identical with ratings as follows:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">Three-phase, 11 kV, 2000 hp, efficiency = 90 %, 0.85 pf, overload withstand = 110 % of rated current.</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">The fault currents for faults at different buses are tabulated below:</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:104px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.15: Fault Currents at Different Buses</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Triple Line Fault in Amp</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Double Line Fault in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4860</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4208</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2754</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2385</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">10139</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">8780</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">D</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3983</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3450</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">TMS of R<sub>7</sub> and R<sub>5</sub> are set at 0.1 and 0.3 respectively and the high-set instantaneous setting of relays R<sub>5</sub> and R<sub>3</sub> are set at 700 % and 2000 % of the relay rating respectively. Allow 10 % overload while deciding plug-setting of all relays. Relay R<sub>1</sub> is voltage-controlled overcurrent relay such that its plug-setting reduces to 40 % of set value if voltage collapses below 70 % of rated voltage. Assume</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">1 hp = 735.5 Watts.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Instantaneous time of operation of relays = 0.06 sec.</span></p>\n	</li>\n</ul>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>&nbsp;TMS of phase relay R<sub>2</sub> shall be set at</strong></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'4','4,6,8','1','0','1','2021-07-13 05:58:29','2021-07-13 11:28:29'),(2525,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256583281625658328.jpg\" style=\"height:616px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.38 shows a single line diagram of a portion of a power system network. The relays R<sub>1</sub> to R<sub>7</sub> are normal inverse IDMT overcurrent relays with usual range. All four induction motors are identical with ratings as follows:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">Three-phase, 11 kV, 2000 hp, efficiency = 90 %, 0.85 pf, overload withstand = 110 % of rated current.</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">The fault currents for faults at different buses are tabulated below:</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:104px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.15: Fault Currents at Different Buses</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Triple Line Fault in Amp</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Double Line Fault in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4860</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4208</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2754</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2385</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">10139</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">8780</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:129px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">D</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:155px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3983</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:170px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3450</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">TMS of R<sub>7</sub> and R<sub>5</sub> are set at 0.1 and 0.3 respectively and the high-set instantaneous setting of relays R<sub>5</sub> and R<sub>3</sub> are set at 700 % and 2000 % of the relay rating respectively. Allow 10 % overload while deciding plug-setting of all relays. Relay R<sub>1</sub> is voltage-controlled overcurrent relay such that its plug-setting reduces to 40 % of set value if voltage collapses below 70 % of rated voltage. Assume</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">1 hp = 735.5 Watts.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Instantaneous time of operation of relays = 0.06 sec.</span></p>\n	</li>\n</ul>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>&nbsp;TMS of phase relay R<sub>1 </sub>shall be set at</strong></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'1','4,6,8','1','0','1','2021-07-13 06:06:40','2021-07-13 11:36:40'),(2526,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256586031625658603.jpg\" style=\"height:537px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.39 shows a single line diagram of portion of a power system network. Relays R<sub>1</sub>, R<sub>2</sub> and R<sub>3</sub> are normal inverse IDMT relays. The maximum load current passing through different transmission lines is shown in the figure. The fault currents for faults at different buses are tabulated in table below:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:151px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.16: Fault Currents at Different Buses</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:81px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Triple Line Fault in Amp</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:161px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Double Line Fault in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:81px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4860</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:161px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4208</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:81px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3220</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:161px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2788</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:81px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2408</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:161px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2085</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:81px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">D</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1922</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:161px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1665</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\"><strong>TMS of relay R<sub>3</sub> is set at 0.1. Allow 10 % overload while deciding plug-setting of all relays. P. S. of phase relay R<sub>3</sub> shall be set at</strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'4','4,6,8','1','0','1','2021-07-13 06:07:37','2021-07-13 11:37:37'),(2527,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256590351625659035.jpg\" style=\"height:537px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.39 shows a single line diagram of portion of a power system network. Relays R<sub>1</sub>, R<sub>2</sub> and R<sub>3</sub> are normal inverse IDMT relays. The maximum load current passing through different transmission lines is shown in the figure. The fault currents for faults at different buses are tabulated in table below:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:151px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.16: Fault Currents at Different Buses</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:81px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Triple Line Fault in Amp</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:161px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Double Line Fault in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:81px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4860</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:161px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4208</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:81px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3220</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:161px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2788</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:81px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2408</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:161px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2085</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:81px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">D</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1922</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:161px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1665</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\"><strong>TMS of relay R<sub>3</sub> is set at 0.1. Allow 10 % overload while deciding plug-setting of all relays. P. S. of phase relay R<sub>2</sub> will be set at</strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'3','4,6,8','1','0','1','2021-07-13 06:08:27','2021-07-13 11:38:27'),(2528,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256593091625659309.jpg\" style=\"height:537px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.39 shows a single line diagram of portion of a power system network. Relays R<sub>1</sub>, R<sub>2</sub> and R<sub>3</sub> are normal inverse IDMT relays. The maximum load current passing through different transmission lines is shown in the figure. The fault currents for faults at different buses are tabulated in table below:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:151px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.16: Fault Currents at Different Buses</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:81px\">\n			<p style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></p>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:164px\">\n			<p style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Triple Line Fault in Amp</span></p>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:161px\">\n			<p style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Double Line Fault in Amp</span></p>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:81px\">\n			<p style=\"text-align:center\"><span style=\"font-size:28px\">A</span></p>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<p style=\"text-align:center\"><span style=\"font-size:28px\">4860</span></p>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:161px\">\n			<p style=\"text-align:center\"><span style=\"font-size:28px\">4208</span></p>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:81px\">\n			<p style=\"text-align:center\"><span style=\"font-size:28px\">B</span></p>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<p style=\"text-align:center\"><span style=\"font-size:28px\">3220</span></p>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:161px\">\n			<p style=\"text-align:center\"><span style=\"font-size:28px\">2788</span></p>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:81px\">\n			<p style=\"text-align:center\"><span style=\"font-size:28px\">C</span></p>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<p style=\"text-align:center\"><span style=\"font-size:28px\">2408</span></p>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:161px\">\n			<p style=\"text-align:center\"><span style=\"font-size:28px\">2085</span></p>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:81px\">\n			<p style=\"text-align:center\"><span style=\"font-size:28px\">D</span></p>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<p style=\"text-align:center\"><span style=\"font-size:28px\">1922</span></p>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:161px\">\n			<p style=\"text-align:center\"><span style=\"font-size:28px\">1665</span></p>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\"><strong>TMS of relay R<sub>3</sub> is set at 0.1. Allow 10 % overload while deciding plug-setting of all relays. P. S. of phase relay R<sub>1</sub> will be set at</strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'1','4,6,8','1','0','1','2021-07-13 06:03:04','2021-07-13 11:33:04'),(2529,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256595041625659504.jpg\" style=\"height:537px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.39 shows a single line diagram of portion of a power system network. Relays R<sub>1</sub>, R<sub>2</sub> and R<sub>3</sub> are normal inverse IDMT relays. The maximum load current passing through different transmission lines is shown in the figure. The fault currents for faults at different buses are tabulated in table below:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:151px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.16: Fault Currents at Different Buses</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:81px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Triple Line Fault in Amp</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:161px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Double Line Fault in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:81px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4860</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:161px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4208</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:81px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3220</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:161px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2788</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:81px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2408</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:161px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2085</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:81px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">D</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1922</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:161px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1665</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\"><strong>TMS of relay R<sub>3</sub> is set at 0.1. Allow 10 % overload while deciding plug-setting of all relays. TMS of phase relay R<sub>2</sub> will be set at</strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'2','4,6,7','1','0','1','2021-07-13 06:03:44','2021-07-13 11:33:44'),(2530,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256597261625659726.jpg\" style=\"height:537px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.39 shows a single line diagram of portion of a power system network. Relays R<sub>1</sub>, R<sub>2</sub> and R<sub>3</sub> are normal inverse IDMT relays. The maximum load current passing through different transmission lines is shown in the figure. The fault currents for faults at different buses are tabulated in table below:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:151px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.16: Fault Currents at Different Buses</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:81px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Triple Line Fault in Amp</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:161px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for Double Line Fault in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:81px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4860</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:161px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">4208</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:81px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3220</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:161px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2788</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:81px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2408</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:161px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2085</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:81px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">D</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1922</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:161px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1665</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\"><strong>TMS of relay R<sub>3</sub> is set at 0.1. Allow 10 % overload while deciding plug-setting of all relays. TMS of phase relay R<sub>1</sub> will be set at</strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'4','4,6,8','1','0','1','2021-07-13 05:57:28','2021-07-13 11:27:28'),(2531,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256598011625659801.jpg\" style=\"height:419px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.40 shows a single line diagram of a portion of power system network. Relays R<sub>1</sub> to R<sub>4</sub> are normal inverse IDMT overcurrent relays. The maximum power taken by transmission lines is as follows:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:160px; width:900px\">\n	<caption>\n	<p><span style=\"font-size:18px\"><strong>Table 7.17: Power Flowing in Lines</strong></span></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:72px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Line</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Power in MW</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Power Factor</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:72px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">AB</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">50</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.8</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:72px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">CD</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">20</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.8</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\"><strong>The bracketed figures indicate the fault level in MVA at respective bus. Allow 10 % overload while deciding plug-setting of all relays. TMS of R<sub>4</sub> is set at 0.1. P. S. of phase relay R<sub>4</sub> shall be set at</strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'2','4,6,8','1','0','1','2021-07-13 06:04:22','2021-07-13 11:34:22'),(2532,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256601381625660138.jpg\" style=\"height:419px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.40 shows a single line diagram of a portion of power system network. Relays R<sub>1</sub> to R<sub>4</sub> are normal inverse IDMT overcurrent relays. The maximum power taken by transmission lines is as follows:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:160px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.17: Power Flowing in Lines</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:72px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Line</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Power in MW</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Power Factor</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:72px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">AB</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">50</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.8</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:72px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">CD</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">20</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.8</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\"><strong>The bracketed figures indicate the fault level in MVA at respective bus. Allow 10 % overload while deciding plug-setting of all relays. TMS of R<sub>4</sub> is set at 0.1. P. S. of phase relay R<sub>3</sub> shall be set at</strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'4','4,6,8','1','0','1','2021-07-13 06:19:00','2021-07-13 11:49:00'),(2533,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256601951625660195.jpg\" style=\"height:419px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.40 shows a single line diagram of a portion of power system network. Relays R<sub>1</sub> to R<sub>4</sub> are normal inverse IDMT overcurrent relays. The maximum power taken by transmission lines is as follows:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:160px; width:900px\">\n	<caption>\n	<p><span style=\"font-size:18px\"><strong>Table 7.17: Power Flowing in Lines</strong></span></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:72px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Line</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Power in MW</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Power Factor</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:72px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">AB</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">50</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.8</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:72px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">CD</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">20</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.8</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\"><strong>The bracketed figures indicate the fault level in MVA at respective bus. Allow 10 % overload while deciding plug-setting of all relays. TMS of R<sub>4</sub> is set at 0.1. P. S. of phase relay R<sub>2</sub> shall be set at</strong></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'1','4,6,8','1','0','1','2021-07-13 06:14:02','2021-07-13 11:44:02'),(2534,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256604791625660479.jpg\" style=\"height:419px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.40 shows a single line diagram of a portion of power system network. Relays R<sub>1</sub> to R<sub>4</sub> are normal inverse IDMT overcurrent relays. The maximum power taken by transmission lines is as follows:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:160px; width:900px\">\n	<caption>\n	<p><span style=\"font-size:18px\"><strong>Table 7.17: Power Flowing in Lines</strong></span></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:72px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Line</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Power in MW</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Power Factor</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:72px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">AB</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">50</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.8</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:72px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">CD</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">20</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.8</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\"><strong>The bracketed figures indicate the fault level in MVA at respective bus. Allow 10 % overload while deciding plug-setting of all relays. TMS of R<sub>4</sub> is set at 0.1. P. S. of phase relay R<sub>1</sub> shall be set at</strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'3','4,6,8','1','0','1','2021-07-13 06:14:34','2021-07-13 11:44:34'),(2535,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16256607241625660724.jpg\" style=\"height:419px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.40 shows a single line diagram of a portion of power system network. Relays R<sub>1</sub> to R<sub>4</sub> are normal inverse IDMT overcurrent relays. The maximum power taken by transmission lines is as follows:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:160px; width:900px\">\n	<caption>\n	<p><span style=\"font-size:20px\"><strong>Table 7.17: Power Flowing in Lines</strong></span></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:72px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Line</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Power in MW</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Power Factor</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:72px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">AB</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">50</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.8</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:72px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">CD</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">20</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.8</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\"><strong>The bracketed figures indicate the fault level in MVA at respective bus. Allow 10 % overload while deciding plug-setting of all relays. TMS of R<sub>4</sub> is set at 0.1. TMS of phase relay R<sub>3</sub> shall be set at</strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'2','4,6,8','1','0','1','2021-07-13 06:35:04','2021-07-13 12:05:04'),(2536,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16257174381625717438.jpg\" style=\"height:419px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.40 shows a single line diagram of a portion of power system network. Relays R<sub>1</sub> to R<sub>4</sub> are normal inverse IDMT overcurrent relays. The maximum power taken by transmission lines is as follows:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:160px; width:900px\">\n	<caption>\n	<p><span style=\"font-size:18px\"><strong>Table 7.17: Power Flowing in Lines</strong></span></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:72px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Line</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Power in MW</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Power Factor</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:72px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">AB</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">50</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.8</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:72px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">CD</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">20</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.8</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\"><strong>The bracketed figures indicate the fault level in MVA at respective bus. Allow 10 % overload while deciding plug-setting of all relays. TMS of R<sub>4</sub> is set at 0.1. TMS of phase relay R<sub>2</sub> shall be set at</strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'4','4,6,8','1','0','1','2021-07-13 06:15:11','2021-07-13 11:45:11'),(2537,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16257180381625718038.jpg\" style=\"height:419px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.40 shows a single line diagram of a portion of power system network. Relays R<sub>1</sub> to R<sub>4</sub> are normal inverse IDMT overcurrent relays. The maximum power taken by transmission lines is as follows:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:160px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.17: Power Flowing in Lines</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:72px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Line</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Power in MW</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Power Factor</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:72px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">AB</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">50</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.8</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:72px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">CD</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">20</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:123px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">0.8</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\"><strong>The bracketed figures indicate the fault level in MVA at respective bus. Allow 10 % overload while deciding plug-setting of all relays. TMS of R<sub>4</sub> is set at 0.1. TMS of phase relay R<sub>1</sub> shall be set at</strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'1','4,6,8','1','0','1','2021-07-13 06:04:56','2021-07-13 11:34:56'),(2538,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16257186941625718694.jpg\" style=\"height:441px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>Figure 7.41 shows a single line diagram of portion of a key one-line diagram of a thermal power plant. The fault current at 6.6 kV bus is 11.7 kA and that at 415 V bus is 42.83 kA. Assume that the minimum operating time of IDMT relays used beyond PSM equal to 20 is constant at 2.3 seconds at TMS equal to 1.0. The P. S. of phase relay R<sub>4</sub> shall be set at</strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'2','4,6,8','1','0','1','2021-07-13 05:54:46','2021-07-13 11:24:46'),(2539,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16257220941625722094.jpg\" style=\"height:441px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>Figure 7.41 shows a single line diagram of portion of a key one-line diagram of a thermal power plant. The fault current at 6.6 kV bus is 11.7 kA and that at 415 V bus is 42.83 kA. Assume that the minimum operating time of IDMT relays used beyond PSM equal to 20 is constant at 2.3 seconds at TMS equal to 1.0. P. S. of phase relay R<sub>3</sub> shall be set at</strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'3','4,6,8','1','0','1','2021-07-13 05:53:49','2021-07-13 11:23:49'),(2540,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16257222441625722244.jpg\" style=\"height:441px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>Figure 7.41 shows a single line diagram of portion of a key one-line diagram of a thermal power plant. The fault current at 6.6 kV bus is 11.7 kA and that at 415 V bus is 42.83 kA. Assume that the minimum operating time of IDMT relays used beyond PSM equal to 20 is constant at 2.3 seconds at TMS equal to 1.0. P. S. of phase relay R<sub>2</sub> shall be set at</strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'4','4,6,8','1','0','1','2021-07-13 10:50:43','2021-07-13 16:20:43'),(2541,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16257224491625722449.jpg\" style=\"height:441px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>Figure 7.41 shows a single line diagram of portion of a key one-line diagram of a thermal power plant. The fault current at 6.6 kV bus is 11.7 kA and that at 415 V bus is 42.83 kA. Assume that the minimum operating time of IDMT relays used beyond PSM equal to 20 is constant at 2.3 seconds at TMS equal to 1.0. P. S. of phase relay R<sub>1</sub> shall be set at</strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'1','4,6,8','1','0','1','2021-07-13 05:46:49','2021-07-13 11:16:49'),(2542,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16257225421625722542.jpg\" style=\"height:441px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>Figure 7.41 shows a single line diagram of portion of a key one-line diagram of a thermal power plant. The fault current at 6.6 kV bus is 11.7 kA and that at 415 V bus is 42.83 kA. Assume that the minimum operating time of IDMT relays used beyond PSM equal to 20 is constant at 2.3 seconds at TMS equal to 1.0. TMS of phase relay R<sub>4</sub> shall be set at</strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'3','4,6,8','1','0','1','2021-07-13 05:47:49','2021-07-13 11:17:49'),(2543,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16257227111625722711.jpg\" style=\"height:441px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>Figure 7.41 shows a single line diagram of portion of a key one-line diagram of a thermal power plant. The fault current at 6.6 kV bus is 11.7 kA and that at 415 V bus is 42.83 kA. Assume that the minimum operating time of IDMT relays used beyond PSM equal to 20 is constant at 2.3 seconds at TMS equal to 1.0. TMS of R<sub>3</sub> shall be set at</strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'1','4,6,8','1','0','1','2021-07-08 11:09:11','2021-07-08 11:09:11'),(2544,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16257228291625722829.jpg\" style=\"height:441px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>Figure 7.41 shows a single line diagram of portion of a key one-line diagram of a thermal power plant. The fault current at 6.6 kV bus is 11.7 kA and that at 415 V bus is 42.83 kA. Assume that the minimum operating time of IDMT relays used beyond PSM equal to 20 is constant at 2.3 seconds at TMS equal to 1.0. TMS of phase relay R<sub>2</sub> shall be set at</strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'4','4,6,8','1','0','1','2021-07-13 05:45:49','2021-07-13 11:15:49'),(2545,101,'7.1.5 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16257229711625722971.jpg\" style=\"height:441px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>Figure 7.41 shows a single line diagram of portion of a key one-line diagram of a thermal power plant. The fault current at 6.6 kV bus is 11.7 kA and that at 415 V bus is 42.83 kA. Assume that the minimum operating time of IDMT relays used beyond PSM equal to 20 is constant at 2.3 seconds at TMS equal to 1.0. TMS of phase relay R<sub>1</sub> shall be set at</strong></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.5',NULL,'2','4,6,8','1','0','1','2021-07-08 11:13:22','2021-07-08 11:13:22'),(2546,101,'7.1.9 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><span style=\"font-size:14px\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16257230621625723062.jpg\" style=\"height:453px; width:800px\" /></span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.42 shows a single line diagram of portion of a power system network. The table below gives the magnitude of the earth-fault current for L-g fault at different buses.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:189px; width:900px\">\n	<caption>\n	<p><span style=\"font-size:18px\"><strong>Table 7.18: Fault Currents for L-g Fault at Buses</strong></span></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:148px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for L-g Fault in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:148px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2320</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:148px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1504</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:148px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2173</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">The other data required is as follows:</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Each relay group R<sub>1</sub>, R<sub>2</sub> and R<sub>3</sub> is wired for three overcurrent and one earth-fault protection scheme.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Ground relays R<sub>1</sub>, R<sub>2</sub> and R<sub>3</sub> are normal inverse IDMT overcurrent relays with in-built instantaneous high-set units. The setting range for IDMT unit is 10-40 % of 1 amp in seven equal steps and that for instantaneous unit is 400-2000 % of 1 amp in steps of 50 %.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">P. S. and TMS of R<sub>3</sub> are 10 % and 0.1 respectively.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">% overreach of instantaneous high-set unit is 10 %.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Instantaneous time of operation of high-set unit is 0.06 sec.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Time of operation of a relay beyond PSM equal to 20 is definite and constant as 2.3 seconds at TMS equal to 1.0.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Excitation current of all CTs is 0.03 amp.</span></p>\n	</li>\n</ul>\n\n<p>&nbsp;</p>\n\n<p><span style=\"font-size:14px\"><strong>P. S. of ground relay R<sub>2</sub> shall be set at</strong></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:144px; text-align:justify\">&nbsp;</p>','','1','7.1.9',NULL,'1','4,6,8','1','0','1','2021-07-13 11:39:39','2021-07-13 17:09:39'),(2547,101,'7.1.9 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16257236801625723680.jpg\" style=\"height:453px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.42 shows a single line diagram of portion of a power system network. The table below gives the magnitude of the earth-fault current for L-g fault at different buses.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:189px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.18: Fault Currents for L-g Fault at Buses</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:148px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for L-g Fault in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:148px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2320</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:148px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1504</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:148px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2173</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">The other data required is as follows:</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Each relay group R<sub>1</sub>, R<sub>2</sub> and R<sub>3</sub> is wired for three overcurrent and one earth-fault protection scheme.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Ground relays R<sub>1</sub>, R<sub>2</sub> and R<sub>3</sub> are normal inverse IDMT overcurrent relays with in-built instantaneous high-set units. The setting range for IDMT unit is 10-40 % of 1 amp in seven equal steps and that for instantaneous unit is 400-2000 % of 1 amp in steps of 50 %.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">P. S. and TMS of R<sub>3</sub> are 10 % and 0.1 respectively.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">% overreach of instantaneous high-set unit is 10 %.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Instantaneous time of operation of high-set unit is 0.06 sec.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Time of operation of a relay beyond PSM equal to 20 is definite and constant as 2.3 seconds at TMS equal to 1.0.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Excitation current of all CTs is 0.03 amp.</span></p>\n	</li>\n</ul>\n\n<p>&nbsp;</p>\n\n<p><span style=\"font-size:14px\"><strong>&nbsp;TMS of ground relay R<sub>2</sub> shall be set at</strong></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.9',NULL,'3','4,6,8','1','0','1','2021-07-13 11:40:06','2021-07-13 17:10:06'),(2548,101,'7.1.9 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16257239301625723930.jpg\" style=\"height:453px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.42 shows a single line diagram of portion of a power system network. The table below gives the magnitude of the earth-fault current for L-g fault at different buses.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:189px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.18: Fault Currents for L-g Fault at Buses</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:148px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for L-g Fault in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:148px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2320</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:148px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1504</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:148px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2173</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">The other data required is as follows:</span></p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Each relay group R<sub>1</sub>, R<sub>2</sub> and R<sub>3</sub> is wired for three overcurrent and one earth-fault protection scheme.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Ground relays R<sub>1</sub>, R<sub>2</sub> and R<sub>3</sub> are normal inverse IDMT overcurrent relays with in-built instantaneous high-set units. The setting range for IDMT unit is 10-40 % of 1 amp in seven equal steps and that for instantaneous unit is 400-2000 % of 1 amp in steps of 50 %.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">P. S. and TMS of R<sub>3</sub> are 10 % and 0.1 respectively.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">% overreach of instantaneous high-set unit is 10 %.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Instantaneous time of operation of high-set unit is 0.06 sec.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Time of operation of a relay beyond PSM equal to 20 is definite and constant as 2.3 seconds at TMS equal to 1.0.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Excitation current of all CTs is 0.03 amp.</span></p>\n	</li>\n</ul>\n\n<p>&nbsp;</p>\n\n<p><span style=\"font-size:14px\"><strong>&nbsp;P. S. of ground relay R<sub>1</sub> shall be set at</strong></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.9',NULL,'4','4,6,8','1','0','1','2021-07-13 11:40:34','2021-07-13 17:10:34'),(2549,101,'7.1.9 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16261764941626176494.jpg\" style=\"height:453px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.42 shows a single line diagram of portion of a power system network. The table below gives the magnitude of the earth-fault current for L-g fault at different buses.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:189px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.18: Fault Currents for L-g Fault at Buses</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:148px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for L-g Fault in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:148px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2320</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:148px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">1504</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:148px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">2173</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">The other data required is as follows:</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Each relay group R<sub>1</sub>, R<sub>2</sub> and R<sub>3</sub> is wired for three overcurrent and one earth-fault protection scheme.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Ground relays R<sub>1</sub>, R<sub>2</sub> and R<sub>3</sub> are normal inverse IDMT overcurrent relays with in-built instantaneous high-set units. The setting range for IDMT unit is 10-40 % of 1 amp in seven equal steps and that for instantaneous unit is 400-2000 % of 1 amp in steps of 50 %.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">P. S. and TMS of R<sub>3</sub> are 10 % and 0.1 respectively.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">% overreach of instantaneous high-set unit is 10 %.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Instantaneous time of operation of high-set unit is 0.06 sec.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Time of operation of a relay beyond PSM equal to 20 is definite and constant as 2.3 seconds at TMS equal to 1.0.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Excitation current of all CTs is 0.03 amp.</span></p>\n	</li>\n</ul>\n\n<p>&nbsp;</p>\n\n<p><span style=\"font-size:14px\"><strong>&nbsp;Setting of instantaneous high-set unit of ground relay R<sub>2</sub> shall be set at</strong></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.9',NULL,'2','4,6,8','1','0','1','2021-07-13 11:43:12','2021-07-13 17:13:12'),(2550,101,'7.1.9 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16257243081625724308.jpg\" style=\"height:453px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.42 shows a single line diagram of portion of a power system network. The table below gives the magnitude of the earth-fault current for L-g fault at different buses.</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:189px; width:900px\">\n	<caption>\n	<p><span style=\"font-size:20px\"><strong>Table 7.18: Fault Currents for L-g Fault at Buses</strong></span></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:136px\">\n			<p style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></p>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:148px\">\n			<p style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for L-g Fault in Amp</span></p>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<p style=\"text-align:center\"><span style=\"font-size:28px\">A</span></p>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:148px\">\n			<p style=\"text-align:center\"><span style=\"font-size:28px\">2320</span></p>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<p style=\"text-align:center\"><span style=\"font-size:28px\">B</span></p>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:148px\">\n			<p style=\"text-align:center\"><span style=\"font-size:28px\">1504</span></p>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:136px\">\n			<p style=\"text-align:center\"><span style=\"font-size:28px\">C</span></p>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:148px\">\n			<p style=\"text-align:center\"><span style=\"font-size:28px\">2173</span></p>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">The other data required is as follows:</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Each relay group R<sub>1</sub>, R<sub>2</sub> and R<sub>3</sub> is wired for three overcurrent and one earth-fault protection scheme.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Ground relays R<sub>1</sub>, R<sub>2</sub> and R<sub>3</sub> are normal inverse IDMT overcurrent relays with in-built instantaneous high-set units. The setting range for IDMT unit is 10-40 % of 1 amp in seven equal steps and that for instantaneous unit is 400-2000 % of 1 amp in steps of 50 %.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">P. S. and TMS of R<sub>3</sub> are 10 % and 0.1 respectively.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">% overreach of instantaneous high-set unit is 10 %.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Instantaneous time of operation of high-set unit is 0.06 sec.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Time of operation of a relay beyond PSM equal to 20 is definite and constant as 2.3 seconds at TMS equal to 1.0.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Excitation current of all CTs is 0.03 amp.</span></p>\n	</li>\n</ul>\n\n<p>&nbsp;</p>\n\n<p><span style=\"font-size:14px\"><strong>&nbsp;TMS of ground relay R<sub>1</sub> shall be set at</strong></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:168px; text-align:justify\">&nbsp;</p>','','1','7.1.9',NULL,'1','4,6,8','1','0','1','2021-07-13 11:45:43','2021-07-13 17:15:43'),(2551,101,'7.2.2 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16257245421625724542.jpg\" style=\"height:505px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.43 shows a single line diagram of a portion of a power system network. Bracketed figures show the fault levels for triple line fault on respective buses. The fault currents for L-g fault are tabulated below:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:160px; width:900px\">\n	<caption>\n	<p><span style=\"font-size:18px\"><strong>Table 7.19: Fault Currents for L-g Fault at Buses</strong></span></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:157px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for L-g Fault in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:157px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">6680</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:157px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3564</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:157px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">7400</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">The other data required is as follows:</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Each relay group at all relaying points is wired for three overcurrent and one earth-fault protection scheme.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Relays R<sub>1</sub> to R<sub>11</sub> are directional or non-directional (as per requirement) normal inverse IDMT overcurrent and earth-fault relays. The setting ranges are</span></p>\n	</li>\n</ul>\n\n<p style=\"margin-left:96px; text-align:justify\"><span style=\"font-size:14px\">Overcurrent Units: 50-200 % of 1 amp in seven equal steps.</span></p>\n\n<p style=\"margin-left:96px; text-align:justify\"><span style=\"font-size:14px\">Earth-fault Units: 10-40 % of 1 amp in seven equal steps.</span></p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Maximum Power flowing (under normal load condition) through 220 kV lines is 150 MW at 0.85 pf lag. This includes 10 % overload.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Relaying points R<sub>10</sub> and R<sub>11</sub> feed 66/11 kV substations located at different places. (They are not parallel feeders).</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Time of operation of relays is definite and constant beyond PSM equal to 20 as 2.3 seconds at TMS equal to 1.0.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">TMS of phase and ground relays R<sub>10</sub>/R<sub>11</sub> = 0.1.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">The excitation current of all the CTs is 0.03 amp.</span></p>\n	</li>\n</ul>\n\n<p>&nbsp;</p>\n\n<p><span style=\"font-size:14px\"><strong>P. S. of phase relays R<sub>10</sub>/R<sub>11</sub> shall be set at</strong></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:192px; text-align:justify\">&nbsp;</p>','','1','7.2.2',NULL,'3','4,6,8','1','0','1','2021-07-14 05:15:14','2021-07-14 10:45:14'),(2552,101,'7.2.2 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16257248451625724845.jpg\" style=\"height:505px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.43 shows a single line diagram of a portion of a power system network. Bracketed figures show the fault levels for triple line fault on respective buses. The fault currents for L-g fault are tabulated below:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:160px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.19: Fault Currents for L-g Fault at Buses</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:164px\">\n			<p style=\"text-align:center\"><span style=\"font-size:11pt\">Bus</span></p>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:157px\">\n			<p style=\"text-align:center\"><span style=\"font-size:11pt\">Fault Current for L-g Fault in Amp</span></p>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<p style=\"text-align:center\"><span style=\"font-size:11pt\">A</span></p>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:157px\">\n			<p style=\"text-align:center\"><span style=\"font-size:11pt\">6680</span></p>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<p style=\"text-align:center\"><span style=\"font-size:11pt\">B</span></p>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:157px\">\n			<p style=\"text-align:center\"><span style=\"font-size:11pt\">3564</span></p>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<p style=\"text-align:center\"><span style=\"font-size:11pt\">C</span></p>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:157px\">\n			<p style=\"text-align:center\"><span style=\"font-size:11pt\">7400</span></p>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">The other data required is as follows:</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Each relay group at all relaying points is wired for three overcurrent and one earth-fault protection scheme.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Relays R<sub>1</sub> to R<sub>11</sub> are directional or non-directional (as per requirement) normal inverse IDMT overcurrent and earth-fault relays. The setting ranges are</span></p>\n	</li>\n</ul>\n\n<p style=\"margin-left:96px; text-align:justify\"><span style=\"font-size:14px\">Overcurrent Units: 50-200 % of 1 amp in seven equal steps.</span></p>\n\n<p style=\"margin-left:96px; text-align:justify\"><span style=\"font-size:14px\">Earth-fault Units: 10-40 % of 1 amp in seven equal steps.</span></p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Maximum Power flowing (under normal load condition) through 220 kV lines is 150 MW at 0.85 pf lag. This includes 10 % overload.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Relaying points R<sub>10</sub> and R<sub>11</sub> feed 66/11 kV substations located at different places. (They are not parallel feeders).</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Time of operation of relays is definite and constant beyond PSM equal to 20 as 2.3 seconds at TMS equal to 1.0.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">TMS of phase and ground relays R<sub>10</sub>/R<sub>11</sub> = 0.1.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">The excitation current of all the CTs is 0.03 amp.</span></p>\n	</li>\n</ul>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>P. S. of phase relays R<sub>6</sub>/R<sub>7</sub> shall be set at</strong></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">&nbsp;</span></p>\n\n<p style=\"margin-left:192px; text-align:justify\">&nbsp;</p>','','1','7.2.2',NULL,'1','4,6,8','1','0','1','2021-07-14 05:25:41','2021-07-14 10:55:41'),(2553,101,'7.2.2 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16257250841625725084.jpg\" style=\"height:505px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.43 shows a single line diagram of a portion of a power system network. Bracketed figures show the fault levels for triple line fault on respective buses. The fault currents for L-g fault are tabulated below:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:160px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.19: Fault Currents for L-g Fault at Buses</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:157px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for L-g Fault in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:157px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">6680</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:157px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3564</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:157px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">7400</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">The other data required is as follows:</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Each relay group at all relaying points is wired for three overcurrent and one earth-fault protection scheme.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Relays R<sub>1</sub> to R<sub>11</sub> are directional or non-directional (as per requirement) normal inverse IDMT overcurrent and earth-fault relays. The setting ranges are</span></p>\n	</li>\n</ul>\n\n<p style=\"margin-left:96px; text-align:justify\"><span style=\"font-size:14px\">Overcurrent Units: 50-200 % of 1 amp in seven equal steps.</span></p>\n\n<p style=\"margin-left:96px; text-align:justify\"><span style=\"font-size:14px\">Earth-fault Units: 10-40 % of 1 amp in seven equal steps.</span></p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Maximum Power flowing (under normal load condition) through 220 kV lines is 150 MW at 0.85 pf lag. This includes 10 % overload.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Relaying points R<sub>10</sub> and R<sub>11</sub> feed 66/11 kV substations located at different places. (They are not parallel feeders).</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Time of operation of relays is definite and constant beyond PSM equal to 20 as 2.3 seconds at TMS equal to 1.0.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">TMS of phase and ground relays R<sub>10</sub>/R<sub>11</sub> = 0.1.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">The excitation current of all the CTs is 0.03 amp.</span></p>\n	</li>\n</ul>\n\n<p>&nbsp;</p>\n\n<p><span style=\"font-size:14px\"><strong>&nbsp;P. S. of phase relays R<sub>8</sub>/R<sub>9</sub> shall be set at</strong></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>','','1','7.2.2',NULL,'2','4,6,8','1','0','1','2021-07-14 05:24:59','2021-07-14 10:54:59'),(2554,101,'7.2.2 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16257253041625725304.jpg\" style=\"height:505px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.43 shows a single line diagram of a portion of a power system network. Bracketed figures show the fault levels for triple line fault on respective buses. The fault currents for L-g fault are tabulated below:</span></p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:160px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.19: Fault Currents for L-g Fault at Buses</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:157px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for L-g Fault in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:157px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">6680</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:157px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3564</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:157px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">7400</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">The other data required is as follows:</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Each relay group at all relaying points is wired for three overcurrent and one earth-fault protection scheme.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Relays R<sub>1</sub> to R<sub>11</sub> are directional or non-directional (as per requirement) normal inverse IDMT overcurrent and earth-fault relays. The setting ranges are</span></p>\n	</li>\n</ul>\n\n<p style=\"margin-left:96px; text-align:justify\"><span style=\"font-size:14px\">Overcurrent Units: 50-200 % of 1 amp in seven equal steps.</span></p>\n\n<p style=\"margin-left:96px; text-align:justify\"><span style=\"font-size:14px\">Earth-fault Units: 10-40 % of 1 amp in seven equal steps.</span></p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Maximum Power flowing (under normal load condition) through 220 kV lines is 150 MW at 0.85 pf lag. This includes 10 % overload.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Relaying points R<sub>10</sub> and R<sub>11</sub> feed 66/11 kV substations located at different places. (They are not parallel feeders).</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Time of operation of relays is definite and constant beyond PSM equal to 20 as 2.3 seconds at TMS equal to 1.0.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">TMS of phase and ground relays R<sub>10</sub>/R<sub>11</sub> = 0.1.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">The excitation current of all the CTs is 0.03 amp.</span></p>\n	</li>\n</ul>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\"><strong>&nbsp;P. S. of phase relays R<sub>2</sub>/R<sub>3</sub> shall be set at</strong></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>','','1','7.2.2',NULL,'4','4,6,8','1','0','1','2021-07-08 11:51:55','2021-07-08 11:51:55'),(2555,101,'7.2.2 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16257253711625725371.jpg\" style=\"height:505px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.43 shows a single line diagram of a portion of a power system network. Bracketed figures show the fault levels for triple line fault on respective buses. The fault currents for L-g fault are tabulated below:</span></p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:160px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.19: Fault Currents for L-g Fault at Buses</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:157px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for L-g Fault in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:157px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">6680</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:157px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3564</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:157px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">7400</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">The other data required is as follows:</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Each relay group at all relaying points is wired for three overcurrent and one earth-fault protection scheme.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Relays R<sub>1</sub> to R<sub>11</sub> are directional or non-directional (as per requirement) normal inverse IDMT overcurrent and earth-fault relays. The setting ranges are</span></p>\n	</li>\n</ul>\n\n<p style=\"margin-left:96px; text-align:justify\"><span style=\"font-size:14px\">Overcurrent Units: 50-200 % of 1 amp in seven equal steps.</span></p>\n\n<p style=\"margin-left:96px; text-align:justify\"><span style=\"font-size:14px\">Earth-fault Units: 10-40 % of 1 amp in seven equal steps.</span></p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Maximum Power flowing (under normal load condition) through 220 kV lines is 150 MW at 0.85 pf lag. This includes 10 % overload.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Relaying points R<sub>10</sub> and R<sub>11</sub> feed 66/11 kV substations located at different places. (They are not parallel feeders).</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Time of operation of relays is definite and constant beyond PSM equal to 20 as 2.3 seconds at TMS equal to 1.0.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">TMS of phase and ground relays R<sub>10</sub>/R<sub>11</sub> = 0.1.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">The excitation current of all the CTs is 0.03 amp.</span></p>\n	</li>\n</ul>\n\n<p>&nbsp;</p>\n\n<p><span style=\"font-size:14px\"><strong>&nbsp;P. S. phase of relays R<sub>4</sub>/R<sub>5</sub> shall be set at</strong></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>','','1','7.2.2',NULL,'2','4,6,8','1','0','1','2021-07-14 05:19:41','2021-07-14 10:49:41'),(2556,101,'7.2.2 Refer to the media and select an answer.','','multi','html','<p style=\"text-align:justify\"><img alt=\"\" src=\"https://edupmquestionhelp.s3.ap-south-1.amazonaws.com/hint/uploads/images/16257258771625725877.jpg\" style=\"height:505px; width:800px\" /></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\"><span style=\"font-size:14px\">Figure 7.43 shows a single line diagram of a portion of a power system network. Bracketed figures show the fault levels for triple line fault on respective buses. The fault currents for L-g fault are tabulated below:</span></p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:center\">&nbsp;</p>\n\n<table cellspacing=\"0\" class=\"MsoTableGrid\" style=\"border-collapse:collapse; border:none; margin-left:160px; width:900px\">\n	<caption>\n	<p><strong><span style=\"font-size:18px\">Table 7.19: Fault Currents for L-g Fault at Buses</span></strong></p>\n	</caption>\n	<tbody>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Bus</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:157px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">Fault Current for L-g Fault in Amp</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">A</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:157px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">6680</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">B</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:157px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">3564</span></div>\n			</td>\n		</tr>\n		<tr>\n			<td style=\"border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:164px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">C</span></div>\n			</td>\n			<td style=\"border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:157px\">\n			<div style=\"text-align:center\"><span style=\"font-size:28px\">7400</span></div>\n			</td>\n		</tr>\n	</tbody>\n</table>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:48px; text-align:justify\"><span style=\"font-size:14px\">The other data required is as follows:</span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Each relay group at all relaying points is wired for three overcurrent and one earth-fault protection scheme.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Relays R<sub>1</sub> to R<sub>11</sub> are directional or non-directional (as per requirement) normal inverse IDMT overcurrent and earth-fault relays. The setting ranges are</span></p>\n	</li>\n</ul>\n\n<p style=\"margin-left:96px; text-align:justify\"><span style=\"font-size:14px\">Overcurrent Units: 50-200 % of 1 amp in seven equal steps.</span></p>\n\n<p style=\"margin-left:96px; text-align:justify\"><span style=\"font-size:14px\">Earth-fault Units: 10-40 % of 1 amp in seven equal steps.</span></p>\n\n<ul>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Maximum Power flowing (under normal load condition) through 220 kV lines is 150 MW at 0.85 pf lag. This includes 10 % overload.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Relaying points R<sub>10</sub> and R<sub>11</sub> feed 66/11 kV substations located at different places. (They are not parallel feeders).</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">Time of operation of relays is definite and constant beyond PSM equal to 20 as 2.3 seconds at TMS equal to 1.0.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">TMS of phase and ground relays R<sub>10</sub>/R<sub>11</sub> = 0.1.</span></p>\n	</li>\n	<li style=\"text-align:justify\">\n	<p><span style=\"font-size:14px\">The excitation current of all the CTs is 0.03 amp.</span></p>\n	</li>\n</ul>\n\n<p>&nbsp;</p>\n\n<p><span style=\"font-size:14px\"><strong>&nbsp;P. S. phase of relays R<sub>1</sub> shall be set at</strong></span></p>\n\n<p style=\"margin-left:48px; text-align:justify\">&nbsp;</p>\n\n<p style=\"margin-left:192px; text-align:justify\">&nbsp;</p>','','1','7.2.2',NULL,'1','4,6,8','1','0','1','2021-07-14 05:13:40','2021-07-14 10:43:40'),