Dominion Resources Inc's (D.N: Quote, Profile, Research) 882-megawatt Unit 2 at the Millstone nuclear power station in Connecticut shut from full power Thursday after lightning struck the main transformer, the company told the U.S. Nuclear Regulatory Commission in a report.

The company said the reactor had "an uncomplicated trip."

Electricity traders guessed the unit would return to service over the next few days.

The 2,037 MW Millstone station is located in Waterford in New London County, about 50 miles southeast of Hartford. There are two reactors at the station, Unit 2 and the 1,155 MW Unit 3, which entered service in 1975 and 1986, respectively.

Unit 3 continued to operate at full power.

One MW powers about 1,000 homes in Connecticut.

Dominion, which wholly owns Unit 2, operates the Millstone station for its owners.

Dominion (93.47 percent), Massachusetts Municipal Wholesale Electric (4.8 percent) and Central Vermont Public Service Corp (CV.N: Quote, Profile, Research) (1.73 percent) own Unit 3.

Dominion, of Richmond, Virginia, owns and operates about 28,000 MW of generating capacity, markets energy commodities and transmits and distributes electricity and natural gas to customers in 11 states.