Can I use the MVA method instead the pu method?
3 phase generator serves a 5/25kV transformer rated 6MVA. The generator's subtransient impedance is j0.39pu and the transformer rated impedance is 6%. If the generator is rated 11MVA, its contribution (MVA) under fault condition at the transformer's secondary terminal is nearly?
G connected to transformer
11/0.39 = 28.2MVA
6/0.06=100MVA
Since in series: 100(28.2)/(100+28.2) = 21.997 MVA
If= 21.997MVA/1.73(25kV)
Can I do this? or I am completely off??
3 phase generator serves a 5/25kV transformer rated 6MVA. The generator's subtransient impedance is j0.39pu and the transformer rated impedance is 6%. If the generator is rated 11MVA, its contribution (MVA) under fault condition at the transformer's secondary terminal is nearly?
G connected to transformer
11/0.39 = 28.2MVA
6/0.06=100MVA
Since in series: 100(28.2)/(100+28.2) = 21.997 MVA
If= 21.997MVA/1.73(25kV)
Can I do this? or I am completely off??
