A 100 MVA, 13.8 kV, Y-connected, 3 phase 60 Hz synchronous generator is operating at the rated voltage and no load when a 3-phase fault occurs at its terminals. Its reactances per unit to the machine’s own base are: Xs = 1.00, pu X’ = 0.25 pu, X” = 0.12 pu
Which of the following results is/are true?1
Sub-transient current is 34.85 kA
2
Transient current is 16.73 kA
3
Steady-state current is 4.18 kA
4
The AC component of current in this generator the instant after the fault is 16.73 kA