BLACKOUT PROBE Timeline shows glitches in Ohio's power lines

The investigation is focusing on a plant and lines owned by FirstEnergy Corp.
COLUMBUS (AP) -- Ohio's section of the regional power grid had at least 64 glitches in the four hours before the nation's worst blackout, according to a timeline by the state's utility regulator.
The draft timeline by the Public Utilities Commission of Ohio is consistent with reports showing glitches across the grid that were released earlier by power companies and the joint U.S.-Canadian task force investigating the blackout last month.
The timeline that the Ohio utility regulator sent to Gov. Bob Taft this week shows that most problems involved power plants and major transmission lines that tripped off momentarily or went down completely. The details were first reported Friday by The Plain Dealer of Cleveland.
The Aug. 14 outage darkened homes and businesses in eight states and parts of Canada. The blackout affected 50 million people, shut down more than 100 power plants and knocked Cleveland's water supply off line.
American and Canadian investigators are focusing on failures of a power plant and lines owned by Akron-based FirstEnergy Corp.
No cause identified
The Ohio timeline has been given to the task force and intentionally does not identify a cause of the blackout, regulator spokeswoman Shana Gerber said.
Taft and the task force did not immediately return messages seeking comment.
The timeline includes the 12:05 p.m. trip of circuit breakers at a unit of American Electric Power's plant in Conesville in eastern Ohio.
However, the Ohio report goes further, pinpointing problems -- even some considered minor, like a small line tripping for a few seconds -- that occurred on all parts of Ohio's portion of the grid.
An AEP line in Findlay, for example, tripped for half a second at 3:51 p.m., the timeline shows.
Such brief line trips happen constantly, caused by anything from a bird or a tree limb hitting a line, AEP spokesman Pat Hemlepp said Friday.