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Ohio 'black hole' for electricity before blackout

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  • Ohio 'black hole' for electricity before blackout

    Ohio 'black hole' for electricity before blackout

    COLUMBUS, Ohio (AP) -- In the hours before the nation's worst blackout, several transmission lines in Ohio were carrying massive amounts of power "well above" emergency summer standards before automatically shutting down, a company that owns the lines said Friday.

    American Electric Power owns or co-owns the power lines with FirstEnergy Corp., which is at the center of a U.S.-Canada blackout investigation. The company released the information with a timeline but didn't offer any conclusions about the cause of the outage.

    AEP said it avoided potential widespread outages in its area -- only 14,000 of its customers lost power -- because control systems detected "abnormal operating conditions" and tripped -- or disconnected -- from linked FirstEnergy lines.

    "It is likely that the automated controls tripped some transmission lines moments before they would have burned down because of extremely high power flows out of our system," said Henry Rayne, AEP's executive vice president.

    The region where investigators suspect the eight-state blackout began August 14 had become a black hole, sucking electricity from generators and threatening to burn transmission lines because of the overload, power company officials said. Many power lines automatically shut down to prevent burnout as the blackout spread.

    "Those lines were never designed for that tremendous shot," said Joseph Welch of International Transmission Co. of Ann Arbor, Michigan, which operates Michigan lines.

    At some point, the power transmission systems in northern and southern Ohio separated from each other, causing electricity meant to move through FirstEnergy's system to reverse itself and flow over AEP's system through Indiana and into Michigan, then back to FirstEnergy in Ohio, power company officials say.

    "Something happened in the time leading up to the blackout to the north of us," Pat Hemlepp, spokesman for Columbus-based AEP, said Friday. "Suddenly, the electrons destined for Columbus or Cincinnati or somewhere turned tail and headed north."

    The power outage affected 50 million people in eight states and Canada. It shut down more than 100 power plants and knocked Cleveland's water supply off line.

    The United States and Canada are conducting a joint investigation into the cause.

    While officials were quick to rule out the possibility that the outage was the work of terrorists, the concern that terrorists could launch an attack on the country's energy infrastructure has been high ever since September 11, a federal official said Friday.

    "The three times we've gone to an orange alert (since September 11) has been tied to vague threats to the power grid directly," Pat Wood, chairman of the Federal Energy Regulatory Commission, said during a conference call about the blackouts held by the energy consultancy Cambridge Energy Research Associates.

    Orange is the second highest of five alert levels, which now stands at yellow.

    Wood wouldn't speculate about the series of events that may have caused the blackouts to spread like wildfire, but said the root problem may turn out to be as simple as an untrimmed tree. One of FirstEnergy's lines sagged into a tree during the outage.

    The heavy load of power on the Ohio lines occurred after FirstEnergy's Eastlake power plant tripped off at 1:35 p.m., about two hours before the cascading blackout began, says AEP's timeline and one released by the North American Electric Reliability Council.

    FirstEnergy would not say if it cut back on demand, stopped exporting power or warned the public to cut back on usage after losing electricity at its Eastlake plant.

    If it didn't drop its load, FirstEnergy would have had to use power generated from other utilities to serve its customers and fulfill its exporting contracts, which could cause power surges and overload lines, an industry analyst said Friday.

    "Simply losing a generator is enough to overload lines, if there weren't steps taken to interrupt demand," said Robert Burns, senior research specialist at Ohio State University's National Regulatory Research Institute. "The other companies may not at the time have known what was causing this," Burns added.

    American Electric Power said power was being siphoned out of its territory.

    "A number of the lines were carrying power flows well above the summer emergency rating for the lines because of the massive amounts of power being drawn north from AEP's system," the company said Friday.

    The power siphoning scenario is among many investigators are reviewing.

    AEP said its first failure came at 3:45 p.m. in a line it co-owns with FirstEnergy that comes from a Canton substation. AEP said the line was "abnormal" for 58 seconds. That was more than two hours after the problem at the Eastlake plant.

    A Canton Center-Cloverdale line, for example, had a summer emergency rating of 197 megavolt-amperes, but was carrying 332 megavolt-amperes when it tripped, the company said. The East-Lima-Fostoria line tripped at 2,000 megavolt-amperes, much higher than its summer emergency rating of 1,383, AEP said.

    The company said it was providing the data to the North American Electric Reliability Council (NERC), which is helping in the investigation led by the U.S. and Canadian governments, which took over the probe last week.

    Ralph DiNicola, a FirstEnergy spokesman, said the investigation must look beyond individual utility systems. He said FirstEnergy detected several tripped plants and lines elsewhere on the grid before the Eastlake plant dropped.

    "Simply knowing the direction of power flow doesn't tell you anything," he said.

    The blackout peaked across the Midwest and Northeast at 4:11 p.m.

    Frank Merat, an electrical engineer at Case Western Reserve University, said AEP's automatic control -- a very large circuit breaker -- worked properly, shutting down its system when it sensed a possible overload.

    The problem, he said, is that AEP's control system doesn't alert other utilities' systems to the problem.

    "Everything is so interdependent, but they don't have one big computer overseeing the system. You've got lots of computers overseeing lots of things," Merat said.

    http://www.cnn.com/2003/US/Midwest/08/22/blackout.investigation.ap/index.html
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