UNSYMMETRICAL FAULT CALCULATIONS – PART – 31 – THREE PHASE FAULT AND SINGLE LINE TO GROUND FAULT - PROBLEM

A 33 kV bus bar has a three-phase fault level of 1000 MVA. The negative and zero sequence source reactances are 2/3 and 1/3 of positive sequence reactance. The zero sequence resistance of the source is 50 ohms. A 30 MVA, 33 / 132 kV solidly grounded delta/star transformer having a reactance of 0.2 per unit. Is fed from 33 kV bus. Find fault current and fault MVA at 132 kV bus for the following faults. (a) Three phase fault and (b) Single line to ground fault.