Experts Fear Automated PG&E Technology in North Bay Firestorm

November 01, 2017

NBC Bay Area
By Jaxon Van Derbeken

A common outage-prevention technology that has been blamed for fueling wildfires worldwide may have helped spark the North Bay firestorm, experts say.

The potentially problematic device, known as a recloser, is essentially an automated circuit breaker. When a fault is detected on a power line, the device helps ensure reliable service, according to retired PG&E engineer turned consultant Dan Mulkey.

When a fault “trips” on a line, power would normally be lost, Mulkey said. But the recloser sends three quick test bursts of power back down the line. The jolts test whether a problem might clear up on its own.

“In the first trip, it will then reclose,” said the 42-year PG&E engineer who retired two years ago. If the “fault is still there, it trips out again, and it will reclose one more time. So it’s three shots to lock out…automatically.”

But when a line is down in a windstorm, those “shots” the recloser has sent can repeatedly torch any surrounding brush or trees with as much as 9,000 degree Fahrenheit plasma. That arcing can shower trees and brush with sparks.

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