Determine the rms fault currents on both sides of a 50-kVA, single-phase, 480/120-V transformer with 5% impedance

Question:

Determine the rms fault currents on both sides of a 50-kVA, single-phase, 480/120-V transformer with 5% impedance as shown in the figure below. Assume that all generators behind the bus are large enough to make it an infinite bus and all cable impedances are negligible. Assume 100% voltage before the fault and ignore the normal load current.

CB1 F Infinite bus CB2 50 kVA, 5% Z, 480-120 V Trfr Fault location