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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."
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.
Where were they three days ago, I wonder?
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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.
This is very difficult to do. 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.
Nero-burning ROM for Linux!
says the cause of the blackouts were 3 OHIO transmission lines.
Lastest new reports:
Three failed transmission lines in northern Ohio are the likely cause of North America's largest power blackout, investigators said Thursday
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Ccircuit brakers are not limiting the amount of electrical power that can flow through a high-voltage line
The diameter of cables limits the current and the distance between cables limits the voltage. Lines are designed for a specific capacity. You can't upgrade them only by chaging the breaker.
Besides, they say that a normal circuit breaker would arc across. What would prevent an arc between the ends of their ceramic rods?
If they want to use semiconductors, why don't they use them for the entire line? Or for the coils in the generators? That would make a difference, not some circuit brakers...
Dude, that 102.4% only means that the plant operated more efficiently than normal. The amount of power generated by the core did NOT exceed 100%. However, the generator output exceed the maximum dependaple capability (MDC) as a result of higher conversion efficiency. The MDC is a lower bound on what the plant -as a whole- can reliably deliver to the grid. All it takes to achieve better efficiency is lower than "normal" temperature of circ water to the condenser. This can simply be caused by weather conditions. I've seen nuclear plants whose output could vary by more than 100 MWe over the course of a year, solely due to seasonal changes in ambient temperatures. Lower temperature of heat sink = higher thermal efficiency = higher capacity factor.
for all of us who failed electronics/electrical engineering: blackouts for dummys
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Greg Pallast has some Interesting Comments on the blackout. He cites energy deregulation, passed by George Bush, Sr. under lobbying pressure from Enron (Yes, them again!) Very intersting comments, if true. Politicians and Corporations teaming up to line their own pockets while endangering the public. Nice.
I'm trying to teach myself to set people on fire with my mind... Is it hot in here?
Source: Wired Mag September 2003 - paper copy
Talk about timely articles. The day of the blackout the September issue of Wired was in my mailbox. In this months infop0rn, it describes a plan that Buckminster Fuller dreamed up 30 years ago to connect the world on the same grid. "Electric companies dismissed the notion as pie in the sky - and then proceeded to build such a grid." The article states that all the contries in the Western Hemisphere will be interconnected within the next ten years. About half the countries in the world are interconnected in some way already. Those that aren't connected or can't be is because of a geographical, industrial infrastructure, or politcal nature, ie Cuba, a few contries in Africa like Ethiopia and Sudan and Polynesia, Austrailia, and New Zealand.
The article says that this should smooth out market spikes when demand is high in one region it is almost certainly to be low in another. The US uses about 3.8E+18 kilowatt hours a year with about 71% of the energy used produced from fossil fuels. The US is also the largets importer of electricity, most likely the majority from Canada which produces about 58% from hydropower. France is the leading producer of electricity from nuclear, about 75%, and Brazil from hydro, about 86%.
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.
Likewise, all that waste is sitting around in pools (though warm as they are, I wouldn't want to swim in them) because Carter signed an executive order banning reprocessing (known as Presidential Directive 8, subsequently reaffirmed as President Clinton's Presidential Directive 13.) There are certainly issues to consider with reprocessing, but it's a fact that we wouldn't have all this nuclear waste lying around if we recycled it into useful component elements.
Interesting discussion:
PBS Frontline
University of Minnesota Technology newsletter
They were supposed to have protection systems to prevent a cascade failure like this. Making the protection systems fancier isn't going to help too much if they don't install/maintain them properly.
Actually, the primary purpose of the protection systems in place is to prevent grid trouble from physically destroying generators, transformers, transmission lines and other infrastructure hardware. And they worked, otherwise it would have taken weeks rather than hours to get the grid up again. IIRC, in the blackout of 1965>, major infrastructure damage resulted from a grid collapse and it was from this experince that many of the currently implemeted ideas were learned.
Gentlemen! You can't fight in here, this is the War Room!
uhh hello? I dont know why this is modded to +4 since it's just plain wrong. If you'd actually read the article you linked to and the NYT article you would've known that they're now using BSCCO high temperature superconductors which have critical temperatures well above the boiling point of liquid N2(over 100K).
- "Hear that?! The percolations are imminent! Cease your ingress!"
One might think that from a superficial reading, but no. That article says "Each coil is designed to operate at 35K in cold helium gas cooled by a CryoMech AL-125 cryocooler and four specially designed heat exchangers." That's not an easily reached liquid nitrogen temperature, although it's above liquid helium temperatures. Nitrogen liquifies at 77K at 1 atmosphere. This is more like a medium temperature superconducting system.
Besides the issue with interrupting high currents, this superconductor would help to keep power plants from tripping offline in the first place. When working with very high power, it is difficult to build regulators that can handle enough power. Switches/breakers are much easier to build, but they are only on-off. The superconductor apparently allows for some current regulation by varying the external magnetic fields.
Power plants trip offline because they have only 2 choices: stay online and fry, or go offline and screw all the other plants into taking more burden. This superconductor gives a much better 3rd option: stay online, but only supply the rated capacity of the power plant.