PG&E has been conducting field tests in the Calistoga area to prevent wildfires from sparking due to its equipment, a spokesperson for the utility said.

The Rapid Earth Fault Current Limiter (REFCL) was first installed at a Calistoga substation in 2020 in an attempt to “instantaneously” reduce the energy flowing through faults in lines, such as fallen tree branches or other detritus that could bring down power lines. The lines are supposed to detect fallen wire situations and immediately reduce the flow of electricity.

PG&E has recently settled for millions of dollars for causing wildfires in Northern California such as the Kincade Fire near Geyserville in Sonoma County and the Dixie Fire that spanned multiple counties.

Rapid Earth Fault Current Limiter technology is demonstrated in Australia. (Video courtesy of Victoria Department of Jobs, Precincts and Regions/YouTube)

Since its rollout, the technology has been tested but not perfected. Field testing done this month throughout the Calistoga area in Napa County was a continuance of testing carried out in 2021, which PG&E says was “successful,” and then last month that resulted in an “interruption in service, indicating further adjustments were needed,” PG&E officials said.

The latest testing took place during the morning hours of April 11-15. Deanna Contreras from PG&E said that the tests were successful and no unplanned power outages occurred, which means the technology is working in tandem with existing electrical equipment. The next step is to review the test data collected, Contreras said.

The REFCL technology comes from the Swedish Neutral company and has been used in Australia, PG&E said. The utility says that this is the first time it is being tested in North America.

REFCL is part of PG&E’s “EPIC” testing plan, or Electric Program Investment Charge, which seeks to use radio frequencies, drones, and other analytics to mitigate wildfire risk.