Electricity was cut off to Dulles International Airport last night, and the terminal and runways were plunged into darkness for a total of 16 minutes before the airport's emergency generators switched on, a spokesman for the Federal Aviation Administration said.

No injuries were reported and no flights were diverted, although "a few" inbound flights were delayed, according to the spokesman. He said the control tower contacted aircraft by battery-operated radio.

A spokesman for the Virginia Electric and Power Co. said the power failure was caused when a lightning arrester blew out at a substation serving the airport and about 2,500 other Vepco customers.

It could not be learned last night why the airport's emergency backup system, which is designed to switch on automatically within a minute or so, did not cut in sooner.

According to the spokesman for the FAA, which runs Dulles, a first, brief failure occurred at 8:37 p.m. Emergency generators began operating two minutes later and commercial power was restored at 8:42.

Seven minutes later, power went off again and emergency power did not cut in until 9:03, leaving the airport blacked out for 14 minutes. Vepco restored power at 10:50 p.m.

The spokesman said police cars and other emergency vehicles beamed their lights inside the terminal to provide some illumination during the blackout periods.