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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."
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 --
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.
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There are places where the networks are not touching,and there are places where they are-Boeing's Lori Gunter
Making the protection systems fancier isn't going to help too much if they don't install/maintain them properly.
This is not a simple matter of making the protection systems fancier... this is a fundamentally different approach to preventing cascade failure. It's orders of magnitude more robust (no arcing current, etc, as mentioned in the article) and there is no good reason why we shouldnt' have more robust systems.
These sort of things won't all be maintained properly, however it is my hope that after this blackout the maintainence system is revised to minimize negligence. Having these systems installed will help the well-maintained stations not suffer due to the problems of the ill-maintained... It makes the whole system much fairer and could possibly save a lot of money in the long run.
I also think that advancing superconducting technology is worth this effort alone, as it is a very promising field. A superconducting electric motor for an electric car would only have to be the size of a softball (extremely high magnetic field densities, and of course efficencies). Superconductors are being used in better bandpass filters for things like cellular telephone transceiver towers and possibly even space missions. Superconductors are also used for experiments with NMR quantum computing, and may hold the key to confined fusion (yes, a long way off I know).
You are correct that there is an issue to be addressed with maintainence, however I cannot see how this could do anything but help the situation.
Cheers,
Justin
P.S. Nice Kosh quote!
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.
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.
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.