UPDATE 2-PG&E Calif. Diablo Canyon 2 reactor shut due fire

(Updates with company comment)

NEW YORK, Aug 18 (Reuters) - PG&E Corp's (PCG.N) 1,118-megawatt Unit 2 at Diablo Canyon nuclear power station in California automatically shut on Sunday due to a fire that damaged a transformer, a spokeswoman for the company said.

She could not say when the unit would return to service since workers were still investigating the cause of the fire and developing a repair plan.

She said the fire started about midnight and lasted about 30 minutes and forced the company to declare an unusual event.

An unusual event is the lowest of the U.S. Nuclear Regulatory Commission's four emergency classifications.

PG&E terminated the unusual event within two hours.

The spokeswoman said the company does have another transformer on site that can replace the damaged transformer if necessary.

The 2,240 MW Diablo Canyon station is located in Avila Beach in San Luis Obispo County, about 195 miles northwest of Los Angeles. There are two units at the station: 1,122 MW Unit 1 and the 1,118 MW Unit 2, which entered service in 1985 and 1986.

Unit 1 was not affected by the fire and continued to operate at full power.

One MW powers about 700 homes in California.

PG&E, of San Francisco, owns and operates more than 6,200 MW of generating capacity, markets energy commodities, and transmits and distributes electricity to 5.1 million customers and natural gas to 4.2 million customers in California. (Reporting by Scott DiSavino, editing by Matthew Lewis)