<p style="text-align:justify"><span style="font-size:14px">Faults are inevitable. They do occur. The large fault currents will pass through the equipment of power system. Hence, equipments are required to be short-time rated for these fault currents. The circuit breakers are to be designed to interrupt this high value of fault current. The relay setting is decided based on this fault current. Thus, fault current calculations and fault analysis are very essential not only for existing power system but also while designing and installing the equipments of power system. We will discuss different types of faults, their causes and their consequences. We will also learn the procedure of calculating these fault currents.</span></p>