[142453] in North American Network Operators' Group
RE: Wacky Weekend: NERC to relax power grid frequency strictures
daemon@ATHENA.MIT.EDU (Ingo Flaschberger)
Sun Jun 26 17:44:03 2011
Date: Sun, 26 Jun 2011 23:43:57 +0200 (CEST)
From: Ingo Flaschberger <if@xip.at>
To: Matthew Huff <mhuff@ox.com>
In-Reply-To: <483E6B0272B0284BA86D7596C40D29F9012124453BA0@PUR-EXCH07.ox.com>
Cc: "'nanog@nanog.org'" <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
> 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
