Minor Ground Fault Incident at Grand Coulee Dam

Media Contact: Annette Ross, (208) 378-5322
Lynne Brougher, (509) 633-9503

For Release: October 28, 2013

GRAND COULEE, Wash. - On the afternoon of October 23, 2013, a ground fault occurred above the Grand Coulee Dam Left Power House. There were no injuries nor were there any damage to the lines, generator, or transformer.

The Generator 8 (G-8) penstock was being filled with water to return the unit to service after undergoing maintenance. As the penstock filled, the air released through the vent valve on the face of the dam also forced water out of the vent. The water stream was close enough to an energized power line to cause a path for electricity to flow from the line to the source of the water at the vent outlet. Some minor surface damage occurred to the concrete on the face of the dam at the fault location.

Reclamation is performing technical analysis on the cause of the fault to prevent similar events in the future.

Grand Coulee Dam was completed in 1942 and serves as a multipurpose facility providing water for irrigation, hydroelectric power production, flood control, recreation, fish and wildlife.

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Reclamation is the largest wholesale water supplier and the second largest producer of hydroelectric power in the United States, with operations and facilities in the 17 Western States. Its facilities also provide substantial flood control, recreation, and fish and wildlife benefits. Visit our website at www.usbr.gov and follow us on Twitter @USBR.