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Tuesday, May 29, 2007 A More Robust Grid for ManhattanSuperconducting cables could make power-grid infrastructure more secure. By David Talbot
Supercooled, superconducting power cables have long held the potential to deliver power efficiently, since they offer no resistance losses. Now they're being examined as a way to add redundancy in the cramped quarters of Manhattan's local power grid, potentially protecting against natural disruptions and terrorist attacks. In a city, superconducting cables offer an advantage: they are far more compact than copper wires. And some of the requisite surge protection can be engineered directly into the cables--a feat not possible with copper wires--reducing the need for bulky mechanical circuit breakers in city substations. To develop the concept, the U.S. Department of Homeland Security and New York's major utility, Consolidated Edison (Con Ed), announced last week that they would invest $39 million over the next three years to connect two substations at undisclosed locations in Manhattan, allowing each to take over for the other in the event that one burns out. The effort will use technology from American Superconductor, of Devens, MA, which makes so-called high-temperature superconducting cables ("high temperature" means that they can operate at 90 degrees kelvin) and associated control systems. "It's not a panacea for every system problem, but it would give us more reliability and flexibility and asset sharing," says Steve Kurtz, project engineer at Con Ed, a utility whose grid flaws became evident last summer when a power outage darkened parts of Queens for 10 days. "It would make the grid more resilient." Part of the power grid's shortcoming in New York City--as in many other parts of the country--is the lack of Internet-like cross connections, which would add reliability. The grid's endpoints are substations that typically serve tens of thousands of customers apiece. A single lightning strike or errant squirrel can burn out a substation, leaving tens of thousands of people in darkness until the utility can get the substation back online. The solution is to add cross connections between substations so that others can quickly step in to supply power. Such redundancy could also prove useful during a terrorist attack. But if a city adds connections, it also needs to add more equipment to stop faults from propagating through these new connections. "It sounds pretty good, so why don't they do it?" asks Greg Yurek, CEO of American Superconductor. "The answer is that there is not enough real estate under the streets of Manhattan." To be sure, all this is possible using tried-and-true copper wires and mechanical equipment. But in places like Manhattan, there is no room under the ground for all the extra copper cable--which has to be given some air space to dissipate heat--and no room in cramped midtown substations for new breakers. |
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A New Superconductor
06/06/2008
Comments
ms on 05/29/2007 at 1:16 PM
58
nekote on 05/30/2007 at 6:40 AM
109
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
135
nekote on 06/07/2007 at 8:20 AM
109
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.