Just back from visiting the family in Pennsylvania, where temperatures were hitting the high 90s. It was the kind of sticky, muggy, oppressively hot weather that reminds me why I live in the cool corner that is the Pacific Northwest.
As air conditioners were blasting away everywhere and lights were flickering, I was thinking that grid operators must be calling on every demand-response resource they could.
Back into post-vacation action, I came across an Aug. 10 release [PDF] from PJM Interconnect that confirmed it. The power grid was on emergency status and PJM, in fact, drew a record demand response -- 1,945 megawatts -- equal to a fair-sized city.
PJM also reduced voltage in the overall system by 1,000 MW, explaining those flickers. So I actually lived through the scenario with which I opened "Adventures in the smart grid no. 2." Damned glad they kept those air conditioners on.
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Comments
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ffletcher Posted 6:09 pm
18 Aug 2007
Interesting Topic
In addition to the voltage reduction it is possible to reduce overal demand by reducing the frequency. Frequency reduction has the addition benefit of adding power into the grid. The energy returned to the grid is related to the mass of the spinning turbines and rotors connected to the grid, which can be quite substantial. Typically a system expresses this term in units of MW per .1 Hz deviation.
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Sam Wells Posted 4:14 am
19 Aug 2007
Brown-outs
One of the worst situations was on the outer islands of the Bahamas, which were run by the Bahamian Electric Company. Because of development the little network of diesel generators and transformers quickly became overloaded. Black-outs happened, which is why most residences have their own generators. But the brown-outs were worse, since they de-rated voltage, frequency, and all kinds of things in an effort to keep electricity flowing. This proved to be disastrous.
Air conditioners, washing machines, driers, electric ranges, and all sorts of stuff caught fire or simply blew their motors. Wires melted. Low voltage conditions can actually be worse than a power surge, it turns out.
Bahamians quickly became excellent little electricians, knowing how to wire a house with surge protectors for lightning strikes and low voltage alarm systems; even the lowliest knew to unplug large electrical appliances or turn off the circuit breakers when away from the house. They figured out how to integrate small generators so power could be fed to the right stuff at the right kW ratings.
It's amazing how dumb the average American is about electricity. Get a windmill or a solar panel and you'll be fascinated by how it all works. If 10,000 Abaconians in the out islands can do it with no more than a high school education, I'm sure we can manage ...
/sammie
Onward through the fog
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WWAGD?! Posted 6:17 am
19 Aug 2007
Hot and muggy in Pennsylvania! AMAZING!
Wow! You visited Pennsylvania in August and found temperatures soaring into the 90s...and it was humid!
Stop the presses!
Oh, and electricity grid was failing.
Gee -- that just sounds like everything I remember about the East Coast since moving here to Kent, WA!
John Bailo
Sutext:
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