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Superconductors as Electrical Grid Surge Suppressors
securitas writes "The New York Times published a story about Intermagnetics -- a company that plans to use 'superconductors as valves on the electric-utility power grid, letting their temperature rise to choke off the flow of power,' a day before the largest blackout in North American history. The timing couldn't have been better. On the day of the blackout, Intermagnetics announced a $6 million contract from the Department of Energy to develop and install superconductor 'valve' prototypes by 2006 in the Niagara Mohawk distribution system. Considering that one of the leading theories for the cause of the cascading blackout is a surge in the Niagara Mohawk power grid, this announcement seems incredibly timely."
In related news, NYTimes is considering a namechange to NYFutureTimes
I have a photographic memory for numbers. I know almost a hundred of them.
this announcement seems incredibly timely.
A little too timely.
/me twirls handlebar moustache
Or as Kosh said, "Once the blackout begins, it is too late to order pizza."
One line blog. I hear that they're called Twitters now.
Given the amount of power flowing through these lines, you cannot use a normal or even semi-normal fuse.
A fuse works by breaking the conductor path, stopping the current flow. At high currents and voltages, the breakpoint will heat up, ionize, and provide a LOW impedence path, which is difficult to break.
Some devices that are used to interrupt mains current are switches with contacts immersed in heavy oils, those that use an air blast to disperse the ionized air path, and other more exotic systems.
How is this a storage device? It's supposed to increase its resistance when a large, sudden change in current takes place. In other words, it sounds like it would dampen an oscillation. I don't see how it could "inject" current into the grid.
says the cause of the blackouts were 3 OHIO transmission lines.
This is a great start, especially with the way the power grid is now.
Essentially right now a surge large enough to damage substations creates a large chain effect, where the incoming substation sees the surge, shuts itself down to protect itself, which adds more power to the surge, which heads down to the next station, which shuts off to keep itself from being blown, which adds more power to the surge, etc etc.
With a way to contain a large surge into the system, we could prevent blackouts like the one that occured in NYC in 1977 (Exactly because of this reason). In 1977 a summer storm knocked several high-voltage power lines out of order. Because of the suddenly reduced load, the power tried to flow back to the substation, which knew it couldn't handle it and shut down. This added more power to the grid, which was sent to the next station along the line, which shut itself off, etc. This cycle of power overload, substation shut down happened for about 55 mins till it hit the main generators (which, although they could shut themselves down, had no way to offload this excess power down the line) and took them out for 25 hours.
I said it before, I'll say it again. Get rid of our 30+ year old nuclear reactors (no new orders for units since 1977) and replace them with newer more powerful solutions and second generation solar equipment.
When reactors are running at 102.41% capacity, it's time for an upgrade.
We've got the technology now to produce cleaner, safer, more powerful nuclear reactors - but that Three Mile Island paranoia still looms with us I guess.
Look at European nations, they derive up to 50% of their power from modern nuclear facilites without any problem and no blackouts. The USA? Just 20% of our power comes from Nuclear energy, the rest from coal fired power plants and "peak use" and "daytime use" gas turbine generators.
Hey, I don't want to live right next door to a huge nuke power plant myself, but if it means cleaner, safer, more reliable power I'd be more then happy to.
Looking for hardware (Currently need: Large Etch-a-Sketch) Have one? See my journal!
for all of us who failed electronics/electrical engineering: blackouts for dummys
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Anyone who knows anything beyond EE 101 knows that trying to stop electicity over 30,000 volts is heading for trouble. Unless you have a huge insultor that is at least 500,000 Ohms, the electricty will just jump over it without even slowing down.
And anyone who knows any physics knows that that statement is bullshit without some sort of geometrical context.
Look at all the 350k powerlines out there... You don't see them arcing every day, because it's not voltage the makes the problem, it's electric field strength! These pipes are probably rather long, so the E-field strength that they will be experiencing should be quite small (E-field = potential / distance). The superconductors lose superconductivity during a surge, becoming a resister whose resistance is proportional to temperature. Due to I*R^2 ohmic heating, the resistance will shoot up rather quickly, thus cutting off the surge. Much of the surge's power will be turned into waste heat (I'd hate to have to design that cooling system) but it's much better than the alternative.
It should also be clarified that arcing occurs precisely because circuit breakers, being mechanical, are not large enough to keep the E-field to a level that won't ionize the surrounding atmosphere (allowing arcing).
Disclaimer: I'm a year away from my bachelors in Applied Physics.
Once upon a time, it was discovered that if you cool certain materials below a critical temperature, they lose all resistivity, i.e. superconducting magnets are only superconducting below a certain temperature. Once their temperature exceeds that critical temperature, "quenching" occurs. The resistance suddenly becomes "normal," i.e. dramtically increasing. This can be catastrophic, the temperature and resistance suddenly becoming directly related and both increasing at accelerated rates. All that energy in the magnetic field suddenly becomes heat.
When I was an undergraduate at Rice University, I got to use the NMR machine in the chemistry department. Essentially, it's a large superconducting magnet that is used to investigate the structure of chemical samples with radio waves.
The superconductor is contained in a large steel thermos. The inner layers are cooled by liquid helium (4 K), outer layers by liquid nitorgen (78 K). Superconductors are used because a large amount of current can be used, producing a larger magnetic flux, etc. The more powerful the magnet, the easier the determination of structure.
Every few days the liquid helium and liquid nitrogen would have to be added to maintain the temperature control.
I was warned that if the magnetic every quenched, it would sound like a freight train. Remaining liquid nitogen or helium would boil and the magnet itself would probably melt. One moment it's a multi-million dollar instrument, the next it's a steam whistle with a heart of worthless slag.
I was told that if this happened on my watch, I should run to my car, drive to Mexico, and hope the my professor's hitmen never found me.
Magnets are transported to the location of installation before being cooled and and superconducting is initiated. Once installed, they are precarious to relocate. Major concerns:
1) slight bumps can disrupt internal structures causing annoying variations in the magnetic field- don't be the chemist who brings a wrench in the room and gets it permanently attached to the side of the container
2) loss of temperature control - the quenching phenomenon.
3) a very high-powered magnetic field- you can exactly push down the hallway without causing damage to nearby objects or its own the magetic field
If this quenching was used to control current, it would have to be carefully controlled to avoid catastrophic damage to the superconductor itself. This seems a nontrivial engineering problem.