Baltimore Gas and Electric Co. workers continued to investigate what caused high-voltage lines to go down outside the city of Annapolis, putting on a light show Thursday night before plunging more than 55,000 customers into darkness.
Electricity was restored by 1 a.m. Friday, though work will continue over the weekend, BGE spokeswoman Rachael Lighty said.
The transmission lines disconnected about 9 p.m. Thursday from a tower near Bestgate Road and Generals Highway, an area near the Annapolis Mall.
Anne Arundel County police helped people exit the darkened mall, directing traffic there and at other large intersections in the Annapolis and Crownsville areas, police spokesman Justin Mulcahy said, adding that there were no serious problems. Police reserve officers, volunteers who help the department, assisted with traffic control.
County firefighters responded to calls of neighborhood wires down — including one of a tree that fell and took wires with it — but they appeared to be unrelated to the major outage, said the Division Chief Michael Cox.
People reported hearing security alarms sounding, and neighbors clustered outside wondering what happened.
The power lines that disconnected from a substation were high-voltage lines carrying 115 kilovolts each — enough to cause a spectacular glow in the sky, said Lighty. In contrast, the distribution lines that run in neighborhoods operate at up to 34 kilovolts, she said.
"It's very rare for a transmission line to experience an outage," Lighty said.
The problem was isolated, electricity was rerouted and power restored. "We are taking a look at the electrical distribution equipment that's on the tower and reattaching the lines to the equipment," Lighty said.
During the outage, Anne Arundel Medical Center and the Annapolis city water treatment plant and the sewage pumping stations operated on generator power.
"It could have been a lot worse," said Annapolis Mayor Joshua Cohen.
The rainy, windy evening probably kept some people off the roads, he said, but many shoppers were out in the city Thursday as Annapolis businesses had planned to stay open until 11 p.m.
"Traffic was the biggest issue," he said.
Cohen said off-duty police officers were called to direct traffic at some intersections. At other intersections, the only lights working were traffic signals on battery backup. Public works workers rolled out free-standing stop signs at others.
City police spokesman Sgt. Eric Crane said that between 9 p.m. and 10:30 p.m., city dispatchers received 150 calls, with 23 of those for alarms sounding and two for accidents.Copyright © 2015, Los Angeles Times