This bears repeating..greenspun.com : LUSENET : TimeBomb 2000 (Y2000) : One Thread
After I originally read this in Blistered's post about solar flares, I had to step back and think about it. I don't think many caught the significance of the effect on "the grid". Here's a repost of some of that info. Note in the text that the writer states:
"Voltage regulations need to be within 5 to 10 per cent of a nominal value. If you fall outside that, you generally see a system collapse and the start of a domino effect,"
If this were true, then any cause that would alter voltage regulation beyond the limits could shut down a grid. Is this true? If so, this would make the grid far more susceptible to failure than ever before. What about the so-called dirty electricity? Can anyone verify or dispel this theory?
Here's the original excerpt
Rapidly changing magnetic fields generate currents in any conductors within reach. This is how a dynamo works--except that the magnetic field remains still in these devices while the conducting wires move through it. When a magnetic storm hits the Earth, any networks of conductors that stretch over the same scale as the magnetic fluctuations act like giant dynamos. Hydro-Quebec's transmission lines stretch for over 1000 kilometres. Power lines, telephone lines and even railway lines are all potential conduits for "geomagnetically induced currents" (GICs) of hundreds of amperes. Power companies are vulnerable because their power lines guide the GICs towards sensitive components such as transformers at power stations and substations. A transformer changes a high voltage supply of alternating current into a low voltage supply or vice versa. It consists of a giant doughnut of iron with two sets of windings on each side of the structure. The voltage in one set of windings induces a magnetic field in the iron core, which in turn induces a voltage in the second set of windings. The ratio of the number of windings in the two coils determines the change in voltage. High-performance transformers are delicate machines. They are designed to cope with voltages within a specific range of amplitudes and frequencies. Outside these bounds, the transformer behaves unpredictably. The trouble with GICs is that the voltages associated with them change this delicate balance. In particular, they set up voltages at harmonic frequencies to the ordinary load. These frequencies are transformed but in a way that can rapidly spiral out of control. The result is wildly fluctuating voltages called voltage asymmetries. If the power is not shut down, these can create enough heat to damage the iron core beyond repair. Worse, these fluctuations pass rapidly through the network so that neighbouring transformers also become affected. Within seconds an entire network can collapse as one transformer after another fails. Exactly this happened to Hydro-Quebec's power system that fateful morning. "Voltage regulations need to be within 5 to 10 per cent of a nominal value. If you fall outside that, you generally see a system collapse and the start of a domino effect," says John Kappenman, an expert in the effects of geomagnetic storms at the Metatech Corporation, based in Goleta, California.
-- Rainman (email@example.com), November 26, 1999
I don't know if this is the same idea or not. Two years ago we had a liightening storm. A fire ball went down the powerline out front and houses all around lost TVs, microwaves, computers, fax machines, washer and dryers, etc. We have lightening rods on the house and our roof did a rattling dance and everything went off. After it was over and the dog and I crawled out from under the bed, I went to the braker box. The main breaker had thrown and I could not move it. Had to get an electrician out to fix it. It was all but welded in there. We, however, lost nothing but a fax machine and that came through the phone line as I had forgotten to unplug it. A few nights later, we had just gone to bed when there was a bang and a flash of light. The transformer blew up out along our driveway. There was no electrical storm at the time, so don't know what that was about. But power company had a new one in and running by 2am. Anyway, I think those lightening rods do work!
-- Taz (Tassie123@aol.com), November 26, 1999.
"After it was over and the dog and I crawled out from under the bed..."
Too funny, Taz!
-- Faith Weaver (firstname.lastname@example.org), November 26, 1999.
How about a URL or two for Kappenman's article/post?
What I've heard about geomagnetic storms is that power transformers are the source of the concern, in that the geomagnetic pulse creates eddy currents in the transformer laminations causing excess rapid heat build up.
Taz, the transformer was probably weakened by the lightning strike and just blew when a bit stress hit it.
While I'm on the soapbox Intermatic makes a nice little whole house 2 line surge protector, model IG124OR, 1200 joule (1500?) which wholesales at $60. Everybody should have one of these if they are concerned about dirty power. Please note that this device only will suck up a finite amount of energy and individual surge protectors should stay on items they currently are attached to. This just adds another line of defense.
-- Ken Seger (email@example.com), November 26, 1999.
Rainman: You almost have it right, but not quite.
The 5 to 10% voltage regulation is a standard that is in most contracts for power being supplied between utilities and between utilities and a company. It can vary but the amount of variance and the time allowed (of the variance) can differ. A change of more than the 5 to 10% would not shut down the grid but might cause some lines to trip off. Relays protect the lines. These relays look at various inputs such as current, voltage, and frequency. If the voltage goes down on a particular section, do to a fault perhaps, then the relay trips off that line.
The incident with Hydro-Quebec has been gone into before. All of their grid did not shut down and it didnt cascade to connected grids. The GIC currents that you mention are DC (Direct Currents) not AC. What happened in H-Q was that a piece of equipment called a Static Var Compensator that saw these DC currents and it caused the equipment to trip out. By the way, the equipment has since been modified to reject these DC currents. Its the DC current that can also quickly cause saturation and core heating of a transformer. But they arent so delicate as you think. And the DC doesnt pass through the network to other transformers, etc. The transformers and lines have enough impedance to prevent that.
Taz: Not the same thing. Lightning has so much power, both in terms of amps and voltage that it fried the breaker and jumped across to the house wiring. Lightning however has a very high frequency so it is quickly attenuated.
-- The Engineer (The Engineer@tech.com), November 26, 1999.
Here's the link to the original article.
I'm not even thinking about the solar aspect of it, but if certain areas of the grid go down due to Y2K and high demands are placed on the rest of the grid, will this cause voltage surges that would go outside the bounds of the 5-10% thus crippling the entire grid?
-- Rainman (firstname.lastname@example.org), November 26, 1999.
No. Dont think of the grid as a seamless structure. When there was a bad ice storm a year ago in Virginia the area that had towers knocked down was in the black but the rest of the East was OK. Ditto with the famous black out back in NYC in 1965. I lived in NJ at that time and had lights.
-- The Engineer (The Engineer@tech.com), November 26, 1999.