UNSYMMETRICAL FAULT CALCULATIONS – PART – 32 – DOUBLE LINE TO GROUND AND LINE TO LINE 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) Double line-to-ground fault and (b) Line to Line fault.