nanog mailing list archives

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


From: Jason Roysdon <nanog.20110127 () jason roysdon net>
Date: Sat, 25 Jun 2011 11:03:08 -0700


On 06/25/2011 07:49 AM, Jay Ashworth wrote:
----- Original Message -----
From: "Jussi Peltola" <pelzi () pelzi net>

On Fri, Jun 24, 2011 at 06:29:14PM -0400, Jay Ashworth wrote:
This is gonna be fun, no?

If your definition of fun is spending a year watching an old microwave
clock lose or gain a few minutes.

I don't see how this has anything to do with syncing two generators.
The grid is in sync, and if the frequency of the grid changes (as it does
all the time) it will stay in sync. It has nothing to do with the
absolute frequency.

Perhaps I read the piece incorrectly, but it certainly sounded to *me* like
the part that was hard was not hitting 60.00, but *staying in sync with
others*...

Cheers,
-- jra

Generators all stay in sync.  Generator owners have expensive devices
that sync the phase before the generator is connected to the grid.  Once
a generator is connected to the gird, it will stay in sync - in fact
that is why they have the expensive devices to make sure that they are
in sync before they connect them, as if they are not, it will instantly
jump to being in sync, which may destroy the generator.

I'm not an electrical engineer, but I do IT "Cybersecurity" for a local
utility.  The electrical engineering / power utility side of the house
starts to rub off - but I say this as I might not have all the terms
exactly right.  I follow the FERC/NERC discussions as CIP compliance is
one of my primary job duties.

In fact, if you want to see what happens if you connect a generator out
of phase, just look into the AURORA out-of-phase circuit breaker
re-closing issues which were brought to light last year.  Here's some links:
http://www.atcllc.com/oasis/Customer_Notices/ATCNetworkCustomerMeeting052411_Francis.pdf

Here's another link I read in the last week when trying to get up to
speak more:
http://yarchive.net/car/rv/generator_synchronization.html

Jason Roysdon


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