Lehman Engineering Power Quiz
Consider the following distribution line.
A bolted ground fault occurs from CØ to ground at F1:
- G = generator, grounded Y connected (Ignore its impedance in your calculation)
- TX = transformer, 3Ø, Grounded Y- Delta , 13.2 kv / 480 volts,
1000 KVA, 3% impedance (ZTX)
- ZXL = system line reactance, ZXL = 2% on 1000 KVA base
- F1 = bolted ground fault from CØ to ground (Assume no fault impedance; ZF1 = 0)
- M = 10 HP, 3Ø, 480 volt, Power Factor = 0.8, Transient Reactance (x'd) = 5%
- (All impedances are on 1000 KVA base and 480 base volts)
Calculate the short circuit current for the ground fault at F1.
What current will flow in the unfaulted phases (A & B) during the fault?
Hint: Remember that the transformer secondary is Delta connected.