Northeast blackout probably caused by failure of three Ohio power lines

[NNN0LHI]

http://www.cnn.com/TRANSCRIPTS/index.html

Breaking at top of page. No story yet. What would cause power lines to fail in good weather? I never heard of such a thing? Sounds like something out of Close Encounters Of The Third Kind. Anyone else ever heard of such a thing?

[Don

[andy12]

1. To much voltage

Exess demand combined with shifting power all over the grid...this will eventually cause lines to fail...generally friction which causes heat is the culprit.

[NNN0LHI]

2. Thanks for the info

Do these lines actually heat up to the point that they burn into two pieces, or do they usually stay in one piece until they become carbonized to the point that they lose their conductivity and will no longer carry current? If you know?

Don

[Atlant]

3. They have circuit breakers.

Just like the power lines in the walls of your house are protected
from over-heating by the circuit breakers in your electric panelboard,
long-distance transmission lines also have circuit breakers. They tend
to be a bit more "manual", where the system operators can deliberately
allow the lines to run in an overload condition when circumstances
demand it, but ultimately, the breakers will "trip".

When that happens, it can get very exciting very fast because it
isn't just a 15 Amp, 1650 Watt house circuit. It's a line carrying
power approaching a billion Watts, and all that power doesn't
just vanish; it seeks alternate routes and tends to cause additional
equipment (including whole power plants) to "trip".

And before you know it, sometimes you end up with a
"cascading power failure" as we had yesterday.

Atlant

[Buck Turgidson]

8. Short lesson on transmission lines.

High voltage transmission lines are made of bundles of wires, usually bare aluminum. As the current (power) increases, the wires heat up and begin to soften. If you slowly increase the current in the wires, the line will begin to sag between transmission towers. Imagine a big stretchy piece of taffy held between your hands.

So, curiously, one of the factors that determines the capacity of a transmission line is ground clearance. Overloaded wires can actually touch the ground or trees or bushes between those big towers. The conductors are bare and have no insulation. So what happens when they touch something? That's right, it's a short circuit. Very bad.

Shorts circuits cause nearly infinite current for a very short time. In order to prevent damage to the system, the transmission lines have circuit breakers at each end that open automatically during a short circuit condition. This happens very rapidly, much less than a second. Once the breaker is open, there is no longer any current flowing and the conductors begin to cool down. Eventually, they will shrink right back to their original height. Close those breakers and you can start using that transmission line again.

[NNN0LHI]

9. Thanks to you, Atlant and the others for this information on this subject

I knew a little bit about these lines and the ground clearance needed. Worked for an outfit that was hired by Commonwealth Edison here in Illinois to do brush clearing beneath these lines a long time ago. Could never figure out why they were so worried about a little brush just a few feet off the ground when the wires were way up there? I do now. Learn something new every day. Welcome to DU Buck and Dr. Strangelove is one of my favorite movies by the way.

General Turgidson: Mr. President, we are rapidly approaching a moment of truth both for ourselves as human beings and for the life of our nation. Now, truth is not always a pleasant thing. But it is necessary now to make a choice, to choose between two admittedly regrettable, but nevertheless distinguishable, postwar environments: one where you got twenty million people killed, and the other where you got a hundred and fifty million people killed.

President Muffley: You're talking about mass murder, General, not war!

General Turgidson: Mr. President, I'm not saying we wouldn't get our hair mussed. But I do say no more than ten to twenty million killed, tops. Uh, depending on the breaks.

Don

[newyawker99]

12. Hi Buck Turgidson!!

Welcome to DU!! :toast:

[robbedvoter]

4. So, it was wrong to "Blame Canada"? Will Pataki apologize to Chretien?

What a bunch of incompetents these thugs are! Read here that that plant is owned by a bush pioneer. We are owned by thieves!

[Wonk]

14. Link, re: President of First Energy being a ShrubCo "Pioneer"

link

[jos]

5. A link

http://www.globeandmail.com/servlet/story/RTGAM.20030816.wblackout0816/BNStory/Front/

[AP]

6. Ohio is probably the most Republican state in the country

and the Bush family has more political connections there than in FL, CT and TX (I heard someone say once).

[SadEagle]

7. Primary source.

The NERC (people responsible for preventing this type of stuff) website, www.nerc.com has a nice document listing various failures in chronological order. See http://www.nerc.com/pub_doc/PreliminaryDisturbanceReport.pdf. Apparently some stuff failed in Ohio as early as 14:06 -- more than 2 hours (!) before the collapse.

[htuttle]

10. Thanks for that link!

I've been puzzling over the sharp trading volume increase in a major power backup company's stock that happened 4 hours before the cascade failure (there's a couple of other links to it in GD).

This moves the 'first problem event logged' time back another hour (there were earlier reports of other events logged an hour before the failure). It makes it even more likely that the cascade failure was known to be imminent even earlier that day.

(on edit: usage)

[newyawker99]

13. Hi SadEagle!!

Welcome to DU!! :toast:

[Snellius]

11. Sounds like the culprit is deregulation

This obviously isn't a problem of energy production (but watch the Republicans try to blame this one on environmentalists). It doesn't even sound like a problem with the transmission lines or hardware. What this seems to say is that leaving energy purely to private, unregulated interests creates so much chaos that, even when it fails, they can't even find out why.