SoCal Edison Tests REFCL Tech to Prevent LA Wildfires

Over the last five years, Southern California Edison—the utility that serves Los Angeles—has been testing a way to prevent downed power lines from starting fires. The technology, a kind of power diverter called Rapid Earth Fault Current Limiter (REFCL), detects a current surge caused by power line fault, such as a line struck by a tree, and instantaneously collapses the voltage before a fire can ignite.

According to SoCal Edison’s testing results, posted in December 2022, REFCLs work. In all four testing locations, which the utility conducted among the scrub that grows in the mountains and high desert regions around L.A., the power diverters made the system release 99.99 percent less energy from ground faults compared to Edison’s typical designs. But when devastating wildfires erupted around L.A. last month, the utility hadn’t installed the experimental system more broadly across its territory.

It remains unknown what caused the Eaton, Palisades, and many other wildfires that sparked during dry, high-wind conditions in January. The fires burned tens of thousands of acres in L.A. county and killed nearly 30 people.

SoCal Edison has acknowledged that several of its transmission lines running over Eaton Canyon experienced a surge in current around the time the fire there began. Although that spike in electrical current could suggest Edison’s equipment was responsible for starting the Eaton Fire, the utility maintains that was not the case.

SoCal Edison and Others Test Wildfire Prevention Tech

Electrical infrastructure has been identified or suspected as the ignition source for several of California’s enormous wildfires over the past several years. And even when it’s not the cause, infrastructure is vulnerable to destruction or interruption during wildfires, resulting in blackouts in areas already reeling from the flames.

With wildfires becoming more common and destructive, utilities, engineers and cities are increasingly devoting more resources to finding tech solutions to harden the grid against such fires. “It’s like a COVID moment for wildfire resilience,” says Anukook Lahkina, CEO of the Bay Area wildfire prevention startup BurnBot. The world is coming to grips with the reality of this crisis and working together to figure out solutions.

SoCal Edison’s REFCL technology is the product of an intensive R&D program in Australia led by utilities in the Australian state of Victoria, which began after a downed power cable started the deadly “Black Saturday” bushfires of 2009. In multi-wire setups, REFCLs act as a safety switch to cut the power to only the affected line, preventing a wildfire from sparking without causing a widespread blackout. The technology is now widely used in Europe, and covers an area of at least 40,000 square kilometers in Australia.

REFCLs are one of a variety of solutions in development to prevent or slow the spread of major wildfires. Many utilities have installed their own weather stations,