[RE-wrenches] National grid hertz adjustment

bob ellison reellison at gmail.com
Sun Jun 26 16:40:30 PDT 2011


This will make it interesting to everybody with a grid tie inverter, can we
open up the specs to let them work with the "new test variation"? The other
option is that the inverters will spend a lot more time off line.

 

Bob Ellison

 

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Roy Butler
Sent: Sunday, June 26, 2011 1:45 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] National grid hertz adjustment

 

I saw this as well, came over the AP news wire on Friday, June 24th.
I've been trying to figure out what they hope to gain by allowing more
frequency variation.....puzzling at best!



Roy Butler
NABCEP Certified Solar PV InstallerR
NYSERDA eligible PV & wind installer
Four Winds Renewable Energy, LLC
8902 Route 46
Arkport, NY 14807
607-324-9747
 
www.four-winds-energy.com
 
Although no trees were killed in the sending of this message, 
a large number of electrons were terribly inconvenienced.
 
                


On 6/26/2011 1:31 PM, North Texas Renewable Energy Inc wrote: 

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

 

 
 
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