Generator Fault - Leakage Reactance
Generator Fault - Leakage Reactance
(OP)
I'm trying to determine various faults on a synchronous generator. I received information from the manufacturer -> ie. Xd, X'd, X''d, Xq, X''q ...... The one piece of information that was added that I was not used to seeing was a leakage reactance.
Here are some typical numbers that I have obtained,
X1(leakage) = 0.08 p.u., X2(negative sequence) = 0.22,
X0(zero sequence) = 0.07, X''d = 0.12
When I'm considering a fault (ex. line-to-line), does that leakage reactance come into play in my calculation ? Normally I would treat the short circuit current (p.u) as,
Vpu/(X''d + X2). Or is the leakage reactance already included in the other reactances (i.e. negative sequence) ?
Should I subtract the leakage reactance from the others in my calculations ?
Thanks in advance,
Tony
Here are some typical numbers that I have obtained,
X1(leakage) = 0.08 p.u., X2(negative sequence) = 0.22,
X0(zero sequence) = 0.07, X''d = 0.12
When I'm considering a fault (ex. line-to-line), does that leakage reactance come into play in my calculation ? Normally I would treat the short circuit current (p.u) as,
Vpu/(X''d + X2). Or is the leakage reactance already included in the other reactances (i.e. negative sequence) ?
Should I subtract the leakage reactance from the others in my calculations ?
Thanks in advance,
Tony






RE: Generator Fault - Leakage Reactance
The negative sequence reactance is approximately equal to (Xd" + Xq")/2 Again the leakage reactance is already included in the value you have.
So you can calculate your phase to phase fault currents using Xd" and X2 only.
Dr K S Smith
Mott-MacDonald, Power Systems Division
Glasgow, Scotland.