After alerting regulators to a second fire in a matter of days tied to a falling tree hitting one of its lines, PG&E promised Tuesday to act more quickly to shut down its system at the first sign of trouble in high fire threat areas.
The July 13 Dixie Fire, which has grown to a quarter million acres and is still raging, began several hours after a Douglas fir fell onto PG&E’s Bucks Creek 1101 line in the remote Feather River Canyon.
Critics have since faulted PG&E for not shutting down the line immediately after two fuses blew, cutting power to a nearby dam that morning.
When a lineman arrived several hours later, he found a fire had just started, apparently by the leaning tree hitting the still-live line. The decision to leave the power on came despite the fact that PG&E ranked Bucks Creek near the top of the company’s list for fire danger.
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On Tuesday, PG&E acknowledged that its equipment likely played a role in a second fire, also in Plumas County, which began under similar circumstances to the Dixie Fire, but nine days later.
In its notice to state regulators, PG&E said it had picked up "alarms and other activity" that lasted for 80 minutes before power was partly cut on its Gansner 1101 power line the evening of July 22. It is unclear whether PG&E dispatched a technician or what triggered the partial shut down, however.
The ensuing Fly Fire, which erupted near Butterfly Valley Twain Road and Highway 70, soon merged with the Dixie Fire. PG&E told regulators on Monday that it was on hand when the U.S. Forest Service moved a tree that had been found resting on the Gansner Line.
On Tuesday, PG&E announced changes to how it deals with trouble signs on its system. It said for the rest of this fire season, it will aim to respond to reported faults or outages in high fire areas within 60 minutes or less, equivalent to an emergency priority call.
The company also announced it plans to recalibrate the sensitivity of its fault-sensing equipment to activate earlier, at the first sign of a fault or other trouble, to automatically shut down the power at the trouble spot. The goal, the company said, is "to prevent potential arcs and sparks that could result in fire ignitions."
In the Dixie Fire, PG&E has said the fluctuation that morning lasted only a fraction of a second, not long enough for the normal settings of its automatic equipment to trigger and shut off the line. That meant that while two fuses cut power on the circuit, a third wire was still energized during the hours before the lineman’s eventual arrival.
The company says resetting its shutoff threshold levels could mean more local outages, but stressed "it is an important step to keep PG&E’s customers and communities safe."
For the most at-risk circuits – like one tied to the Dixie Fire – PG&E says it is stepping up safety patrols to spot and counter drought related threats to its system.
"We will be tenacious in our efforts to stop ignitions from our equipment," CEO Patti Poppe said in a statement announcing the changes. "We recently announced our initiative to underground 10,000 miles of overhead power lines, which will significantly reduce the risk we face in the years to come. Today, we are outlining additional safety actions to combat the real and evolving wildfire threat present today."