Power-Line Restart Device Implicated in Past Wildfires

November 02, 2017

San Francisco Chronicle
By David R. Baker

On the night of Oct. 8, as a windstorm raged across the North Bay, some of Pacific Gas and Electric Co.’s local power lines were programmed to try to restart themselves in case service was interrupted — even if they were knocked to the ground or tangled in a tree.

Devices called reclosers — similar to automated circuit breakers — were set to shoot pulses of electricity through lines that tripped off. If conditions on the line seemed normal, the reclosers would automatically restart power.

If, however, the lines were in contact with branches or brush, those pulses of electricity could have started a fire.

State investigators are trying to determine whether PG&E’s power lines played a role in triggering the wildfires that swept across Wine Country that night, destroying whole neighborhoods and killing at least 43 people. No cause has been determined.

Reclosers are a key tool for preventing blackouts, but they have been implicated in wildfires before. The danger they pose is significant enough that two of California’s three investor-owned utility companies — San Diego Gas & Electric Co. and Southern California Edison — routinely reprogram them during fire season so that the devices don’t automatically try to restart power lines.

PG&E, California’s largest utility, has been conducting a pilot program this year to do the same thing, spokesman Keith Stephens said. Some of PG&E’s reclosers in the North Bay were part of that pilot program, he said. When the windstorm hit, they functioned as programmed and let power lines that went dark stay dark.

But other reclosers in the area were not part of the experiment, Stephens said. Instead, they were programmed to try up to three times to restart power lines that had shut down.

The California Department of Forestry and Fire Protection, which is investigating the possible causes of the fires, won’t say if it is looking specifically at reclosers. But state Sen. Jerry Hill wants the potential role of these devices examined.

“Frankly, not turning off the reclosers could have started many if not all of the fires,” said Hill, D-San Mateo.