Superconducting cables are one-tenth the size of copper wires. What's more, they can handle surge protection within the cable itself without requiring new sets of bulky breakers. Superconducting materials, which are based on a flexible ceramic called yttrium barium copper oxide, can tolerate a certain power load. At every point up to that maximum, they carry current with zero loss. But the moment the maximum is exceeded, the superconductors become highly resistive and stop propagation of surges. "Depending on the number of wires you put in, you can carry more current without losses, and you can design the cable in terms of having the right amount of resistance" in the event of power surges, says Alexis Malozemoff, chief technology officer at American Superconductor. Of course, if the superconducting cable becomes resistive, it can burn up, so some hardware is needed to prevent such damage. The company says that unspecified associated control systems will handle this problem effectively. "Necessity is the mother of invention," says Yurek. "You can put [fault protection] in the cable, with some other proprietary technology," which he says is more space efficient. However sensible this might be, it won't be simple. It will take more than a year just to put all the pieces together in laboratories. "You have to design it, then build it, then develop testing protocols, then [do] full prototype tests, then analyze the data, then develop a design specification for installation," says Kurtz. The hope is that the concept will be proved by August 2008. Actual construction won't happen before 2010. High-temperature superconductors were born two decades ago. American Superconductor found a way to commercialize the material by making a flexible version of the ceramic and nudging the temperature requirements up to a more-manageable 90 degrees kelvin. That temperature can be reliably maintained using liquid nitrogen for cooling. While superconducting cables--including some transmission lines in Columbus, OH, Albany, NY, and Long Island--are slowly making headway, the Manhattan project marks a new milestone, says Yurek. "Con Ed is deciding they are willing to put these superconductors in their grid. It's a heck of a validation point, to say the least." |
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A New Superconductor
06/06/2008
Comments
ms on 05/29/2007 at 1:16 PM
64
nekote on 05/30/2007 at 6:40 AM
114
But, this is nuts.
More robust?
Exactly the opposite - more brittle.
The devil here is the absolute necessity for a continuously operating active element - cooling - that millions of people would be depending on.
Murphy's law says it's gonna' get screwed up.
It begs for a catastrophic failure.
And worst, 10 or 100 times as many customers will be affected, whenever the required cooling fails.
In the 1965 and 1977 NorthEast blackouts, underground power distribution cables cooled with oil almost suffered catastrophic burn out because there was no emergency source of power to pump the cooling oil. It took *2* massive power failures, *BEFORE* that shortcoming was corrected!!!
And this is going to operate at 90 degrees Kelvin?
A relatively unknown temperature region, in the vast commercial and industrial sectors.
The wider the area serviced by fewer extremely high capacity links run ever closer to their capacities, the greater the risk of longer term / extended failures (months / years, until destroyed links can be replaced) that will affect greater numbers of people.
Very substantial redundancy and seemingly un-naturally generous excess capacity are needed to minimize that disaster probability. That means greatly increasing the total costs of such an already expensive active cooling system.
It sounds very attractive to be able to increase the amount of power on a single link by a factor of 10 or 100 or 150. The down side is the unacceptible impacts to those dependent on such links, when they fail. Even more so when catastropic failure may literally mean no electric power during the many months (years?) to replace the failed (underground!) links.
To make an extremely exagerated case to illustrate, what if all of NYC's electrical power passed through a few super massive ultra high capacity links? And one link catastrophically failed? Overburdening the remaining fewer links? And required, say, 3 years to replace?
It would seem the obvious alternative is for there to be many more, smaller, electric power "generators", rather than ever higher capacity / density electric power transmission lines.
james_filippi on 06/21/2007 at 1:30 PM
1
dmm on 06/05/2007 at 12:46 PM
136
nekote on 06/07/2007 at 8:20 AM
114
Further, what sense does would it make to have an *active* / high maintenance / cantankerous / less than 100% available "emergency" system? It is not going to be activated / charged up / cooled down, for use, in the midst of an emergency. So, pay to keep such a system up and running, but not in operational use? Left in "standy" and not used?
In practice, it would work the other way around. The old style (current) *passive* conductors would more likely be kept as the fall back "emergency" (albeit more limited?) alternative.