Wacky Weekend: NERC to relax power grid frequency strictures
if at xip.at
Sun Jun 26 16:43:57 CDT 2011
> 2) Allowing transformer fields to collapse. Even in phase, without a
> delayed transition ATS you can end up with a partially collapsed
> transformer field with a new field being created at non-ground state.
> This can cause a transient back wave that can snap circuit breakers.
> Yep, this one happened to us a few times before we switched to a delayed
> ATS, was a PITA to debug and resolve.
a transformer should be switched to the network when phase is at
highest/lowest point, not at zero.
zero: highist current
highest/lowest point: lowest current
because it's a coil.
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