Useless High-Voltage Power Lines Risk Sparking California Fires (yahoo.com) 42
"A line idle for decades has been accused of starting the LA area's deadly Eaton Fire," writes Bloomberg, describing California's abandoned power lines as "a fire risk hiding in plain sight."
[Abandoned power lines] fall out of use, either because they've been replaced or because the power plants they once connected to the grid shut down... Sometimes the utilities that own idled lines disconnect them from the power grid, cutting off the flow of electricity through the cables. Other times, they don't, keeping them energized. California regulations require the companies to remove power lines they don't anticipate using again, but there's no set deadline. The companies can keep idled lines in place if they foresee needing them in the future, so long as they're regularly inspected and maintained.
Even those that have been unplugged from the grid can potentially pose a danger. The line under scrutiny due to the Eaton Fire is owned by Edison International's Southern California utility and was retired in 1971. Under normal circumstances, it carries no electricity, according to the company. Lawyers suing Edison allege that a January 7 power surge on a nearby, active line created a magnetic field that briefly re-energized the dormant cable, setting off the sparks that ignited the blaze. Edison said in a state filing that it is investigating that theory. State investigators have yet to announce a cause for the fire.
A 2019 fire that burned 77,700 acres (31,444 hectares) was started by an old power line for a plant that closed in 2001, according to the article. PG&E, the state's largest utility, "hadn't removed it, and it stayed connected to the grid, energized." [PG&E] agreed to remove 72 permanently abandoned transmission lines — representing about 260 miles (418 kilometers) of dormant cables. The work could cost as much as $268 million spread over 10 years, the company estimated at the time. PG&E had removed 64 of the idled lines by the end of 2024, according to a spokesman.
"At the right conditions, failing idle facilities can pose significant wildfire and safety risks," PG&E said in its plan to remove the equipment.
Thanks to long-time Slashdot reader larryjoe for sharing the news.
Even those that have been unplugged from the grid can potentially pose a danger. The line under scrutiny due to the Eaton Fire is owned by Edison International's Southern California utility and was retired in 1971. Under normal circumstances, it carries no electricity, according to the company. Lawyers suing Edison allege that a January 7 power surge on a nearby, active line created a magnetic field that briefly re-energized the dormant cable, setting off the sparks that ignited the blaze. Edison said in a state filing that it is investigating that theory. State investigators have yet to announce a cause for the fire.
A 2019 fire that burned 77,700 acres (31,444 hectares) was started by an old power line for a plant that closed in 2001, according to the article. PG&E, the state's largest utility, "hadn't removed it, and it stayed connected to the grid, energized." [PG&E] agreed to remove 72 permanently abandoned transmission lines — representing about 260 miles (418 kilometers) of dormant cables. The work could cost as much as $268 million spread over 10 years, the company estimated at the time. PG&E had removed 64 of the idled lines by the end of 2024, according to a spokesman.
"At the right conditions, failing idle facilities can pose significant wildfire and safety risks," PG&E said in its plan to remove the equipment.
Thanks to long-time Slashdot reader larryjoe for sharing the news.
Ground out of service lines. (Score:2)
Lines that are not energized should be grounded out; not sure why these were not.
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Lines that are not energized should be grounded out; not sure why these were not.
Probably because of meth heads, they can't steal the copper if the line is live (though they will try).
Re:Ground out of service lines. (Score:5, Informative)
Power lines aren't made out of copper, they are made out of steel-reinforced aluminum (ACSR). Copper is too heavy and too expensive to be practical to use for long distance power lines.
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Moreover, you can see the fuses are open at the end of the line.
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Thanks. Can you explain why they aren't buried, or at least designed in such a way that if they break they immediately de-energize and don't start a fire?
I'm guessing the answer is cost, but you would think with the recent massive fires and insurance pay-outs the economics of that would have changed somewhat.
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In western europe HV power lines (except the 6 digit voltage ones) are generally buried in cable guides within city limits and expecially within housing areas. Clearly the US - or california anyway - doesn't believe thats important.
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HV power lines are very expensive to bury. They go long distances don't benefit from co-locating services such as in your neighborhood where at some point the entire area was dug up to install all manner of storm water, sewage, telecoms, etc. You find the same thing with long distance utilities, as soon as you get outside of the suburb boundary you'll find water mains and sewage pipes are run above ground too.
As for de-energising, there's three technical points.
1) How do you detect a break? What's the diffe
Re: Ground out of service lines. (Score:1)
High Voltage lines aren't typically "easily accessible", they are typically up on towers, not utility poles running thru neighborhoods.
If meth heads were trying to scavenge the wire, I think we'd see reports of meth heads dropping to their death from towers...
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If meth heads were trying to scavenge the wire, I think we'd see reports of meth heads dropping to their death from towers...
It's not a frequent occurrence, but it does happen. I remember an article several years back here in Florida of some idiots who thought it would be a good idea to steal wires from the utility poles. Spoiler alert: it ended badly for the would-be thieves.
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High Voltage lines aren't typically "easily accessible", they are typically up on towers, not utility poles running thru neighborhoods.
If meth heads were trying to scavenge the wire, I think we'd see reports of meth heads dropping to their death from towers...
Uh, how many other meth-ods of death have you seen reported?
If methheads were dying from cannibalism, most of mainstream society wouldn’t have a damn clue. Never seen a single report on the news. We simply know they just die off. Somehow.
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Lines that are not energized should be grounded out; not sure why these were not.
Probably because of meth heads, they can't steal the copper if the line is live (though they will try).
This week, on California NeoGraphic..
(Narrator, ala Attenborough) “And we see here, the elusive methhead in its natural habitat, foraging for..”
* BZZZZZIZZIZZZZLE-ZIZZZZ-ZIZZZZZ-POW *
(Narrator) “Ah! It appears this methhead has developed a unique cooking method. They can run quite fast too, running ‘round like that on fire. Quite a lovely color of flame, if I do say..”
Re: Ground out of service lines. (Score:1)
Meth heads stealing the lines for scrap seems like a win-win for the "remove a potential fire source on the cheap" problem.
Or, if we insist the utility does it all, they could start prioritizing the segments closest to energized lines and go back later for the isolated segments too remote for this induction risk to arise.
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Meth heads stealing the lines for scrap seems like a win-win for the "remove a potential fire source on the cheap" problem.
Guess that depends on if methheads read signs. Like ones that read “live wire”.
A methhead running around on fire, IS the fire hazard.
physics (Score:2)
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physics / engineering answer: no idea what the theory is or how plausible it is.
lawfare / social engineering answer: Why go to Vegas when you can gamble on suing an "evil corporation" (especially one that's practically a state owned enterprise) instead ? What are the chances that a jury will believe PG&E's "experts'" mumbo jumbo excuses? These people have profits! And they charge money! Pretty clear they're guilty.
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physics / engineering answer: no idea what the theory is or how plausible it is.
lawfare / social engineering answer: Why go to Vegas when you can gamble on suing an "evil corporation" (especially one that's practically a state owned enterprise) instead ? What are the chances that a jury will believe PG&E's "experts'" mumbo jumbo excuses? These people have profits! And they charge money! Pretty clear they're guilty.
Betting on Guilt, is not the challenge here.
Go ahead. Tell me the odds and how much you’re laying down on Punishment.
ACTIAL Punishment.
Yup. Thought so.
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>"The live and disused lines presumably run closeish and parallel to each other at some point (e.g. when they reach the power plant). Current spike on the live line could induce a current spike on the disused line"
Yes, it is possible, although I doubt the lines are close enough to create enough charge to do anything (like arcing), especially on just shorts runs. But if the line is de-energized, wouldn't it be trivial and cheap to just open every fuse down the line so there is no chance that can travel
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If this occurs it is essentially an act of God and Edison should not be liable for an act of God..
Something such as a nearby lightning strike can induce significant voltage in ANY long piece of metal. Including unused wiring, including In-use wiring or unrelated wiring such as ethernet cables or coax that doesn't normally carry significant voltage. Also including random metal objects such as the guard rails along an interstate. A direct hit would also energize them and create a shower of sparks th
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So, the lines themselves are steel conductors. This makes them susceptible to electromagnetic flux.
You could have an inductive coupling happen from a nearby energized wire that experiences a power surge. That is what is being posited by lawyers. Whether or not they can prove that it was enough to cause the line to spark and start fire is another thing.
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You could have an inductive coupling happen from a nearby energized wire that experiences a power surge.
In theory. It's the principle that allows a transformer to work. The problem with this idea is power lines are not wound tightly close together in parallel over long distances like in the turns of a transformer coil. Instead power lines are run w/feet or more average separation; so there is minimal interaction due to distance and any induced currents will be a tiny insignificant amount compared t
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What if there is chronic oversupply of electricity in the lines and corona discharge becomes an issue in energizing nearby lines?
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Corona discharge can be an issue, but this is just an effect of ionizing the air - the energy losses are in the form of heat and light. It does not impart significant current or charge into nearby lines. Just a few volts. Corona discharge will create a sufficient charge to destroy sensitive electronics, but not enough to power anything,
Re: physics (Score:2)
How close together do these cables have to be to each other and what kind of voltage level can be induced this way? Are they running energised and inactive lines together? Where were the sparks between and how much voltage is required for that?
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Or whether or not that constitutes fault/negligence. This is act of god territory if that theory holds up
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How much electricity overproduction is there? (Score:1)
If they're using unused parts of the grid to store excess production and still producing even more power so that it surges and the lines are so overloaded that they corona discharge, why are we still talking about energy scarcity?
Re:How much electricity overproduction is there? (Score:4, Informative)
That's not how any of this works.
Unused parts of the grid can't store energy - these unused CONDUCTORS can not store power.
Power surges are uncontrolled releases of power - think when a capacitor array meant to smooth out power ripples fails short and suddenly discharges everything it had stored.
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When they whine about transmission losses, are they ignoring the fact that they've got way more electricity in the grid than they need to satisfy demand? Why would capacitors fail unless there was oversupply (see dialectric breakdown)?
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Why would capacitors fail unless there was oversupply (see dialectric breakdown)?
Capacitors do not address oversupply, they do not store significant amounts of power. They are used for power factor management since a significant portion of grid loads are inductive. Additionally capacitors can fail for a variety of reasons including chemical breakdown even when completely disconnected. Dielectric breakdown isn't the only reason.
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Grid capacitors are not designed to smooth out power ripples, they are designed to correct power factor on a system that has a significant amount of inductive load on it. Smoothing power is done with either batteries (new), or momentum of spinning heavy machinery (traditional) such as a steam turbine itself. The stability is maintained by the momentum of lots of generators and consumers on the grid working in tandem (think of 10 people pushing a car, if one person stops the car doesn't suddenly stop moving)
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That's probably what happened, they kept cramming more and more electrons into a few runs of wire setting up a growing magnetic field until they ran out of room, then at some point the magnetic field collapsed and the back EMF caused arcing.
All they had to do was connected a 5-cent 1N4148 snubber across it and it would never have happened. Maybe someone could point this out to the lawyers suing Edison. I'd be happy to act as a self-proclaimed expert witness for them.
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Your "self-proclaimed expert" testimony would be laughed out of court before you could even sit down.
I understand the absurdity of putting a diode on a high tension line, but the legal staff would not. The court room would be full of blank looks and vacant stares from those who see electricity and most of science as voodoo magic talk. They would only laugh once a couple of paid experts told them it was ok to do so. Not much different than most of the trolls around here.
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Your "self-proclaimed expert" testimony would be laughed out of court before you could even sit down.
I understand the absurdity of putting a diode on a high tension line, but the legal staff would not.
An “expert” testimony isn’t one when it’s bitch-slapped down by the prosecution armed with a 18-year old apprentice electrician and the NEC code book. This is a legal case involving billions in damages, not an illegal lemonade stand. Only thing absurd is your assumptions on legal tactics.
can anyone explain the math here? (Score:2)
can anyone explain how it would cost $1.03 Million to remove a mile worth of cable when it cost 300-400K to install a mile of HV cable?
re- $268 million cost and 10 years to remove 260 miles of cable.
Tip - Just tell people there is copper in those lines, they'll be gone by sunrise. (yes, i know HV lines don't have copper... but the thieves might not know better)
a cable that was abandoned 54 years ago is still on the list of "anticipated to be used" again lines... that is some ever hopeful thinking... bet th