New Tools for Keeping the Lights On

http://www.nytimes.com/2013/08/01/business/new-tools-for-keeping-the-lights-on.html

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RENSSELAER, N.Y. — After the lights went out for 50 million people from the Northeast to the Midwest on Aug. 14, 2003, investigators found readings from two obscure instruments that would have given them an hour’s warning — plenty of time to solve the problem if the devices had been wired to provide a stream of critical data.

Now, a decade after the largest blackout in American history, engineers are installing and linking 1,000 of those instruments, called phasor measurement units, to try to prevent another catastrophic power failure. When the work is done, the engineers say, they will have a diagnostic tool that makes the old system seem like taking a patient’s pulse compared with running a continuous electrocardiogram.

Gilbert C. Bindewald III, a program manager at the Energy Department, which has spent about $200 million to encourage their installation, said the instruments were “shedding light on the science that’s occurring behind the scenes, within the grid.”

Phasor measurement units work by measuring the rhythm of current at different points on the power grid. Readings at every point within each of the three North American grids — one covering the eastern two-thirds of North America, one covering the West, and one covering Texas — are supposed to be basically the same. If the measurements differ, it can be a sign of imminent collapse. When the current is flowing properly, phasor measurement units record normal readings — about as exciting as “watching paint dry,” in the words of Peter K. Lemme, a senior electrical engineer at the New York Independent System Operator, which runs New York’s grid. As Mr. Lemme spoke, he looked at a real-time display of phasor measurement units across the state.

But then he replayed New York records from an afternoon three weeks ago when a capacitor, a device that helps maintain voltage, suddenly failed at a substation near Utica. In response, measurements taken at an electrical substation near Rochester registered an enormous shock on a graph. In Leeds, south of Albany, the disruption was considerably milder. The disturbance gradually petered out, like a playground swing that slowly comes to rest.

If that glitch had been large enough to threaten a statewide power failure, the new devices could have alerted the engineers to the impending crisis and given them time to react, for example, by shutting down a part of the system to avoid cascading power failures. Tracy A. Flippo, the vice president for transmission operations at the Tennessee Valley Authority, said the devices could provide “precursor information” before a collapse.

The hope is that they could help prevent or at least limit a large-scale blackout like the one that happened a decade ago.

In 2003, as northern Ohio ran short of generation and transmission because of a combination of neglect, mismanagement and human error, circuit breakers took major transmission lines out of service. The power failure then cascaded across 600 miles, eight states and Canada. New York, Cleveland and Detroit went dark, as did Toronto and sections of New Jersey, Pennsylvania, Connecticut and Massachusetts. In New York office buildings were evacuated, thousands of commuters were stranded, and hospitals were flooded with patients suffering in the stifling heat.

“Somebody in Ohio could have recognized that we either need to raise generation or shed load,” said Richard Dewey, senior vice president of the New York Independent System Operator. Or, he said, New York could have seen trouble coming and insulated itself. The two units scrutinized after the blackout, one in Detroit and one in Cleveland, showed the strain.

Other changes to the grid should help, too. The federal government, for example, has given an industry group the authority to set standards. That group, the North American Electric Reliability Corporation, has levied substantial fines against companies that failed in tasks like trimming trees or testing equipment. Untrimmed trees and improper procedures for testing equipment have caused widespread power failures in recent years.

Joel deJesus, a former director of compliance enforcement at the corporation, said that in his view the large fines had been effective. “Wrists have been slapped pretty hard,” he said.

The network of phasor measurement units offers a technological advantage.

So far hundreds of phasor measurement units have been installed across the country, including 48 in New York.

Before then, the operators of the New York grid had only scattered data points within the state. For years they have been mostly blind to the grid outside New York, receiving only a few readings from devices at the borders with New England, Quebec, Ontario, and a region that includes Pennsylvania, New Jersey and Maryland.

But by the end of 2014, officials at the Energy Department said, they anticipate that all 1,000 phasor measurement units will be in operation and linked to one another. The next step, they said, was to figure out how to better present the flood of data to human operators in a useful way.

“The question is, How do we cue them to an event that a computer might be able to see coming?” said Mr. Bindewald of the Energy Department. Initially data will be integrated into computer displays, and later it may be used to set off automatic protective actions that would prevent or limit blackouts.

Experts argue that such a system could easily pay for itself. The 2003 blackout cost billions of dollars in lost economic output.