Re: [LEAPSECS] power grids and leap seconds

From: Tom Van Baak <tvb_at_LEAPSECOND.COM>
Date: Tue, 30 Sep 2003 12:36:31 -0700


Can you elaborate on "some reports". I have been
asking this question for years and have not yet
found a definitive answer.

Recently I talked with the power company speaker
at the ION GPS conference about synchronization
-- who appeared very familiar with the issues of grid
phase angle synchronization (1/60th of a second) --
but was not aware of any leap second issues.

My understanding is the power company's tolerance
is loose enough that a couple of seconds over a day
is within spec so a leap second would be lost in the
noise. I also observe this when I monitor daily mains
frequency and time.

Since synchronization is done at the 60 cycle level
it could be leap seconds have as little effect as leap
days to the power company (except they bill all day
on Feb 29 but leap seconds are "free").


----- Original Message -----
From: "Steve Allen" <sla_at_UCOLICK.ORG>
Sent: Tuesday, September 30, 2003 11:54
Subject: [LEAPSECS] power grids and leap seconds

> One open question regarding leap seconds has been what to do with
> power grids so that clocks with motors that run synchronously with the
> AC power will experience 86400 * (50 or 60) cycles in a UTC day even
> if there is a leap second. Some reports have indicated that many
> grids adjust their frequencies on the day of a leap second such that
> such clocks will retain sub-second accuracy.
> In light of recent world events on power grids, I'll offer that this
> might no longer be considered as a relevant issue. The grids should
> just keep atomic frequency. Clock owners appear likely to need to
> reset them much more often than every leap second.
> --
> Steve Allen UCO/Lick Observatory Santa Cruz, CA 95064
> Voice: +1 831 459 3046
> PGP: 1024/E46978C5 F6 78 D1 10 62 94 8F 2E 49 89 0E FE 26 B4 14 93
Received on Tue Sep 30 2003 - 12:38:37 PDT

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