For decades, utility companies have relied on customers telling them when their lights have gone off as a sign that there may be a broader power disruption. The utilities then send workers to drive along mile after mile of power lines, looking for tiny devices little red circular tabs that have popped up, signaling the source of the problem in the network.
That approach could now be on its way out as the electrical grid becomes smarter. Utilities across the country are experimenting with new sensor and communications systems that can monitor the flow of electricity and pinpoint failures more quickly and, perhaps, even help avoid them.
Last summer, over a stormy Fourth of July weekend in Pennsylvania, where Orange & Rockland Utilities is using a system from Tollgrade Communication, electric company workers were able to figure out where there was trouble on a line and send repair crews out before any customers called them.
In another case, the system helped workers locate and fix a faulty part, avoiding a larger problem.
Eventually, whatever was failing inside would have probably have failed catastrophically, said Francis W. Peverly, Orange & Rocklands vice president for operations. With the system, he added, We can really narrow the area of investigation when an event takes place.
The flow of current along the high-voltage transmission lines that cross the country is well monitored, and the growth of smart meters has increasingly allowed utilities to read when the power goes down at individual homes, experts say.
But most disruptions occur in the distribution grid millions of miles of medium-voltage lines connecting substations to buildings where electric companies have had little visibility.
Failures are becoming more and more prevalent and more widespread, said Edward H. Kennedy, chief executive of Tollgrade, which made its name testing copper cable for the telecommunications industry and has moved into applications for the developing smart grid. A failure in one area will ripple through, and it can take multiple states out, at a cost of as much as $200 billion a year in lost economic activity, he added.
But with the new generation of sensors, utilities are beginning to be able to see where the problems are and even what is causing them, whether a squirrel on a transformer or a tree limb on a power line. As a result, experts say, repairs are faster and more efficient.
With these distribution sensors, they can send a truck right to the fault location and, much more importantly, I think, they can send it there with the right equipment because they know whats failed, said Jay Apt, a director of the Carnegie Mellon Electricity Industry Center. Saying that in the long run use of the sensors could increase reliability and decrease costs, he added: In general, Im a fan of this stuff.
In Detroit, DTE Energy, which serves about 2.2 million customers in the city and southeastern Michigan, has installed more than 100 of the Tollgrade devices small boxes the size of bread loaves that attach to the electric lines and can send a detailed status message when the power goes down as part of a pilot program. Haukur Asgeirsson, power systems technologies manager at DTE, said the company was happy with the results so far, especially the potential for predicting power failures.
Source: The New York Times
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