[RE-wrenches] National grid hertz adjustment

[North Texas Renewable Energy Inc]

This article in the local paper sounds a little like potential trouble for
grid connected inverters. I looked around on the NERC www site without
finding the report mentioned. Any other wrenches seen anything about this
experiment?

Jim Duncan

By Seth Borenstein The Associated Press

  WASHINGTON -- A yearlong experiment with the nation's electric grid could
mess up traffic lights, security systems and some computers -- and make
plug-in clocks and appliances like programmable coffee makers run up to 20
minutes fast.

  "A lot of people are going to have things break, and they're not going to
know why," said Demetrios Matsakis, head of the time service department at
the U.S. Naval Observatory, one of two official timekeeping agencies in the
federal government.

  Since 1930, electric clocks have kept time based on the rate of the
electrical current that powers them. If the current slips off its usual
rate, clocks run a little fast or slow.

  Power companies now take steps to correct it, keeping the frequency of the
current as precise as possible.

  The North American Electric Reliability Corp., which oversees the U.S.
power grid, is proposing an experiment that would allow more frequency
variation without corrections, according to a June 14 company presentation
obtained by The Associated Press.

  The test is tentatively set to start in mid-July.

  Tweaking the power grid's frequency is expensive and takes a lot of
effort, said Joe McClelland, head of electric reliability for the Federal
Energy Regulatory Commission.

  "Is anyone using the grid to keep track of time?" McClelland said. "Let's
see if anyone complains if we eliminate it."

  No one is quite sure what will be affected. This won't change the clocks
in cellphones, GPS or even on computers.

  But wall clocks and those on ovens and coffee makers -- anything that
flashes "12:00" when it loses power -- may be a bit off every second, and
that error can grow with time.

  VCRs or DVRs that get their time from cable systems or the Internet
probably won't be affected, but those with clocks tied to the electric
current will be off a bit, Matsakis said.

  According to the June presentation, East Coast clocks may run up to 20
minutes fast over a year, but West Coast clocks are only likely to be off by
eight minutes. In Texas, it's only an expected speedup of two minutes.


  Read more:
http://www.star-telegram.com/2011/06/24/3178359/test-of-electric-grid-could-
be.html#ixzz1QOzHwezw


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