[time-nuts] accurate 60 hz reference chips/ckts

[Gary E. Miller]

Yo All!

Jeremy wrote:

> I'm surprised Vlad is seeing as much as six seconds differential
> but maybe I don't understand the experiment. I've done measurements
> of the line frequency here in California and never seen much
> variation.  

I live in Central Oregon.  Next to the Pacific Intertie and the Paccific
DC Intertie.  Near the Round Butte Dam, Pelton Dam, and other power
generating dams.

The Interties connect the massive hydropower generation of the Columbia
River system with southern California.

The hypropower system includes the best technology of the 1930's, 1940's
and 1950's.

I've had converstations with some of the dam operators about how
they keep frequency.  Pretty simple really.  Huge tonnages of spinning
steel and copper being pushed by falling water.  The water is regulated
by flapper valves.  Pretty stable short term.

Now imagine when a 300MVA intertie blows over, or is burned by a fire,
and instantly disconnects.  Or a steel mill shuts down for the day, or...

The electrical backpressure to the generators drops, so the generators
speed up, increasing the line frequency and voltage.

When this happens, the dam operators literally pick up the phone, and
talk to the other dams to decide what to do.  Usually that involves
one or more dams closing down a few flapper vavles.

That is how the short term frequency of your local power line is
controlled.

The control room also has a AC synchronous clock, off the power line, 
and an accurate digital clock.  Once a day they manually get the
AC clock to agree with the digital clocl.

None of this is rocket science, don't use it for anything you need
any accuracy for.

RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
	gem at rellim.com  Tel:+1 541 382 8588

	    Veritas liberabit vos. -- Quid est veritas?
    "If you can’t measure it, you can’t improve it." - Lord Kelvin
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