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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.
Wow, I suppose this isn't too surprising, but it isn't every day you see an established company have their stock increase by 17% in one day.
-- jetlag --
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!
Energy traders, power producers and chemical engineers warned yesterday that the UK could face blackouts on the scale experienced in the US and Canada on Thursday night or substantial disconnections at the very least.
1 9996,00.html ' | tr -d ' '
echo ' http://www.guardian.co.uk/uk_news/story/0,3604,10
There are places where the networks are not touching,and there are places where they are-Boeing's Lori Gunter
The fix is to force MaxLoad less than Supply.
This can be done by replacing the local
stepdown transformers that convert from
17KVA Power Lines to the 220/110V 3 Phase
local Power Lines with saturation mode
transformers that will not allow more
than their maximum rated power to pass.
Power Stations can be protected by
Superconducting Air Gap Transformers
that inherently limit the transfer of
power to the rated capacity of the
station. Power Stations would then be
able to stay online through a major
overload without damage.
Any major overload or failure of the
Transmission Grid would cause a brownout
but would not cause a blackout.
Any localized overload would cause a
local browout without causing any
voltage or current instabilities on the
high voltage Power Lines.
for all of us who failed electronics/electrical engineering: blackouts for dummys
This comment does not represent the views or opinions of the user.
Utilities have been testing various superconductive devices for decades, but nobody has deployed them in volume. Superconducting generators have been built by GE and others, but they only offer an 0.5% efficiency improvement over conventional machines. That's not enough to compensate for the added complexity of running a big machine at cyrogenic temperatures.
If this technology worked at liquid nitrogen temperatures, it might have a chance. But anything that needs to go colder than that is probably going to be more expensive and less reliable than what's used now. Scroll down to the end of the article and see the comments from utility companies.
Look who's doing this: General Atomics and LANL, the senior activity centers for over-the-hill bomb designers.
If room-temperature superconductors are ever developed, all this will change, but right now, this is basically big-budget overclocking.
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?
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.
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.
Very true - as a student I used to work at a superconductor research lab that did this kind of work. We would run 100kA through a superconducting coil cooled with liquid nitrogen as part of our experiments, creating a magnetic field with about 3 megaJoules of stored energy. One day a tech mis-wired part of a safety circuit that was used to dump the energy at the end of the experiment run (and then very nicely faked his check-off sheet afterward), and the superconductor heated up so fast it vaporized the one inch aluminum stabalizing rod it was attached to as well as several hundred gallons of liquid He. A nine inch port blew out of the top venting all the (now gasseous) helium into the lab and we all ran like hell to avoid being smothered by the sudden lack of O2 in the room.
Nobody got injured (except the tech, who got fired), but I couldn't help but think about the alternate scenario where the lab staff somehow got trapped inside the room, and the last thing I'd hear before passing out would be "We're all gonna die!" in a Mickey Mouse helium voice.
These devices don't have much to do with the recent US blackouts. They are intended to help manage high short circuit currents in electricity transmission and distribution networks.
As electricity transmission networks grow larger and more interconnected, the current that flows following a short circuit also grows. The maximum level of this short circuit current is a critical parameter when selecting circuit breakers, as all circuit breakers you have must be rated to interrupt the highest possible level of short circuit current that can occur. As transmission networks get larger, eventually you begin reaching circuit breaker short circuit ratings, and the fun begins. You can either start wholesale replacement of your circuit breakers at around $100-200k each, depending on the voltage, or you start splitting up your transmission network to reduce maximum short circuit currents.
What the devices in this article are intended to do reduce short circuit currents, without affecting normal load current. Under normal load conditions they will behave as a super conductor, but under fault current conditions they will rapidly revert to a high resistance, and hence reduce to fault currents to within circuit breaker ratings.
Unfortunately the 'liquid nitrogen' aspect of them makes them impractical for real world, large-scale use. Power transmission equipment routinely has uptimes measured in years (recent blackouts excepted of course), and until room temperature, uncooled superconductors come along, I believe this technology is unlikely to be more than an academic curiosity.