Task Force Reports
by John J. Fialka, Staff Reporter
WASHINGTON -- Three power-plant failures, a grass fire that shorted out a large power line and a tree branch that shut down another line are among the chain of events that started the nation's largest blackout.
Just what caused the blackout remains unknown as a joint U.S.-Canadian task force continues investigating the events of Aug. 14. A timeline released by the task force makes it clear that at 3:41 p.m. EDT, the transmission system in northern Ohio was losing the voltage necessary to keep its power flowing. Read the timeline)
By 4:10 p.m., according to the timeline, the normal clockwise flow of electricity around Lake Erie "began flowing in a giant loop counterclockwise," sucking power from Pennsylvania to New York to Ontario and into Michigan in an attempt to feed the growing power losses in Ohio.
Three minutes later the cascade that darkened much of the Northeast and parts of Ontario was complete. U.S. Secretary of Energy Spencer Abraham and Canadian Minister of Natural Resources Herb Dhaliwal, who head the task force, cautioned that the events in the timeline don't necessarily indicate what triggered the blackout or caused the cascade.
The task force listed events that occurred after noon on Aug. 14. Outages earlier that day are still being examined.
The first failure came at 12:05 p.m. when a small power plant at Conesville, Ohio, shut down. Pat Hemlepp, a spokesman for Columbus-based American Electric Power Co. just north of Detroit shut down. Spokesmen for both companies said the plants were restarted and operating again before the blackout and didn't cause any power imbalances in their systems.
At 1:31 p.m., a plant east of Cleveland owned by Akron, Ohio-based FirstEnergy Co. shut down. Spokesman Ralph DiNicola said operators, sensing low voltage, were adjusting the plant, trying to raise its voltage when it shut down. It didn't restart. Mr. DiNicola said the low voltage may have resulted from large power transactions moving through the area from other utilities.
From 2:02 p.m. to 3:41 p.m., according to the timeline, there were four failures of large power lines in the area. A grass fire in southwest Ohio caused one which, in turn, caused a line to short circuit. Next, two more lines, both owned by FirstEnergy, shut down.
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