nanog mailing list archives

RE: Wacky Weekend: NERC to relax power grid frequency strictures


From: Ingo Flaschberger <if () xip at>
Date: Sun, 26 Jun 2011 23:43:57 +0200 (CEST)

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.

Kind regards,
        Ingo Flaschberger



Current thread: