Failed transformer thought to have caused campus power outage

A brief power outage that shut down electricity to the entire campus Thursday afternoon was most likely the result of a failed potential transformer at the Palou Substation near Forsythe Hall, said Mike Goff, director of utilities. Utilities staff initially thought the outage was caused by problems with PG&E transmission service, which is interconnected with the Cardinal Cogen power plant at the substation, but saw leaking fluid around a transformer Friday morning, Goff said. "We're not ruling out PG&E," but a failed potential transformer could create a power surge like the one that caused the campus power system to automatically shut down on Thursday, he said. A potential transformer, a special type of transformer that allows meters to take readings from electrical service connections with higher voltage than a meter can normally handle, is much smaller than the three main transformers at the substation, Goff said.

Power went off at 3:22 p.m. and systems began automatically restoring power to most buildings six minutes later, said Steve Briscombe, power system manager. Campus electricians restored power to the balance of the buildings and electrical service was fully restored to the campus by 3:40 p.m., he said.

The outage did not interrupt power to Stanford Hospital, although it did temporarily affect the generation of chilled water and steam, which is used in the hospital's air conditioning and heating systems and sterilizers, Goff said.

Facilities Operations is currently upgrading the substation, resulting in the system being "somewhat more susceptible" than normal, Goff said. "We were lucky we could come back up so quickly."