Alternator fault current

[nawao]

I need help to calculate the fault currents (phase to phase, phase to neutral and phase to earth) of a 110kVA generating set, 415/240V, 50hz.
The rectance values given by the manufacturer are as follow:
X"d 0,082
X'd 0,14
Xd 3,51
Xo 0,005
Xq 2,11
X"q 0,102
The time constants:
t'd 100ms
t" 10ms
t'do 2555ms
ta 15ms

 

[hdpeng]

Assuming this is a stand-alone generator (doesn't parallel w/ another generator or utility source), and there are no motor loads on it:

AFC(P-P) = [1,000 * kVA] / [E(P-P) * sqrt(3) * X"d], &

AFC(P-G or N) = [1,000 * kVA] / [E(P-P) * 3 * X"d], or

AFC(P-G or N) = AFC(P-P) / sqrt(3)

as long as you don't have any resistance grounding on the neutral (N), where 'AFC' = Available Fault Current, 'G' = Ground, & 'P' = Phase.

 

[nawao]

Thanks for your contribution, Sir. I appreciate :grin: