Energy Northwest reconnected its 1,190-megawatt Columbia Generating Station to the Northwest Power grid late Saturday night, five days after an equipment malfunction caused an unplanned shutdown.
Energy Northwest said operators are slowly raising power levels and expect to reach 100 percent within 72 hours of restarting.
The plant shut down at 11:24 p.m. Dec. 18 following a malfunction at the Bonneville Power Administration’s nearby Ashe Substation. The substation handles all the electricity produced at the Richland plant.
The malfunction caused the 500 kilovolt line that connects the plant’s main output transformers to the substation to reject the load. A primary breaker that was supposed to open was slow to do so, but a secondary system kicked in an opened other breakers, causing the plant to separate itself from the grid and shut down.
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“I’m proud of the way the team responded in safely shutting down the plant and in their continued focus in getting us ready to return to 100 percent power,” said Bob Schuetz, the plant’s general manager.
Columbia Generating Station is Washington’s lone nuclear plant and the third largest power plan in the state. It sends enough power to the Northwest grid to power a city the size of Seattle.
The plant had been on its way to a record generation year when the shutdown occurred.