One of the topics we covered in an introduction to power systems class was using zero/positive/negative sequence networks to analyze faults in networks. For many problems, this requires setting up positive and negative sequence networks and their equivalent impedance.
My understanding is that balanced/static (?) components have equal positive/negative sequence impedance, while this can be different for generators (I think we're limiting ourselves to synchronous generators).
On to the real question: in one of the examples we are working out the fault current of a SLG fault, and a table is given with different negative/positive sequence impedance for the generator (as I would expect) but according to the solutions, the equivalent negative sequence impedance is the same as the equivalent positive sequence impedance (even though the generator impedance is used to calculate it).
So, what gives? Is this a special case for SLG faults, an approximation, or perhaps just a mistake?
(pretty much the entire faculty seems to be on vacation, and as a Physics major I don't know that many people that know this stuff... thanks in advance!)