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Where There's Smoke: Circuit activity, wildfires spark system-hardening efforts

By Susan DeGrane | Jun 15, 2023
wildfire on grid

It takes very little to start a wildfire.

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It takes very little to start a wildfire. Sparks from a boat trailer chain hitting the pavement, flying ashes from a fire pit, a lit cigarette, fireworks, a car driving on a flat tire, trains putting on the brakes or lightning, coupled with drought conditions and resulting dry vegetation, can all spark disaster.

On May 11, 2022, the Coastal Fire burned more than 150 acres in the Laguna Hills area of Southern California, destroying multiple homes.

That same day, Southern California Edison (SCE) submitted an electric safety incident report to the California Public Utilities Commission’s Safety and Enforcement Division (CPUC- SED).

“Our information reflects circuit activity occurring close in time to the reported time of the fire, 2:43 p.m.,” the report stated.

In 2022, CPUC-SED investigated eight other wildfires with possible correlations to circuit activity, cable faults and circuit interruptions. The blazes prompted corresponding electric safety incident reports filed by SCE, Pacific Gas & Electric (PG&E), San Diego Gas & Electric and PacifiCorp.

One fire engulfed 570 acres, another 500 acres, another 20 acres and another 9.6 acres. The largest covered 4,000 acres, resulting in damage to utility poles owned by San Diego Gas & Electric, but the actual cause of the fire is not known.

Though electric utilities account for only about 10% of wildfires in California, according to CPUC, the severity and frequency of wildfires in recent years prompted the state to require utilities to take preventive action and formulate wildfire mitigation plans.

Taking action

In 2019, Gov. Gavin Newsom signed Assembly Bill (AB) 1054 into law to enhance the prevention and mitigation of catastrophic wildfires, including those related to utility equipment.

AB 1054 added Section 8389 to the Public Utilities Code. This law requires electric utilities to establish safety committees, submit board-of-­director-level reporting to the CPUC on safety issues and file quarterly reports notifying CPUC and the state’s Office of Energy Infrastructure Safety of progress in implementing their wildfire mitigation plans.

As a result, California’s electric utilities are doubling down on efforts to harden off infrastructure and trim back vegetation.

“They’re all putting in a huge effort,” said Jim Stapp, president of Western Line Constructors Chapter Inc. “And once you start, you never quit. You just keep going.”

To avoid liability and stay compliant, utilities are hustling to replace bare transmission lines, old wooden poles, old fuses and exposed circuits where birds tend to nest. They also must monitor circuit activity and weather, develop a system to inform customers of public safety power shutoffs and limit the scope of power outages and shutoffs.

The Western Line Constructors Chapter represents 57 line contractors in California, Nevada, Utah, Idaho, Wyoming, Montana and Colorado. Some have taken on system hardening work in California or responded to fire restoration efforts that have included building back better.

Last March, SCE submitted its latest wildfire mitigation plan to the Office of Energy Infrastructure Safety, along with a press release boasting that the company had “reduced the probability of wildfires associated with its utility equipment by 75 to 85 percent since 2018.” That effort included the installation of 4,400 miles of covered conductor.

SCE is an Edison International company and one of the nation’s largest electric utilities. It serves a 50,000-square-mile area inhabited by 15 million residents in central, coastal and southern California.

“Generally speaking, the work has picked up,” Stapp said, who is also president of PAR Western Line Contractors LLC, Rancho Cucamonga, Calif. “PAR has installed hundreds of miles of covered conduit in California high-hazard wildfire zones.”

Those areas include the Sierra, Angeles, San Bernardino and Cleveland National Forests, as well as several mountain ranges, lower elevation forests and grasslands.

“As a contractor, I feel our customer [SCE] is doing as much as they can to harden the system, and I’m glad to be part of it,” Stapp said. “It’s a significant amount of work in comparison to other types of work we do, and it’s very important.”

Pole replacement

Edison has been at the forefront of pole replacement, Stapp said. 

“Their system is vast. We’ve been installing poles with fire wrap. The fire wrap extends up from the base of poles 20–30 feet. We’ve also been installing steel and fiberglass poles,” he said. “In some areas, we’ve installed sub-transmission systems with concrete bases and steel tops.”

The customer is also inner-setting the newer poles and replacing old wire with covered conductor, resulting in shorter spans. This means less sag and reduced chance of sparks or other problems, Stapp said.

Composite poles and cross-arms offer advantages as well, being more durable and less susceptible to fire and insect damage.

Other upgrades for SCE include installation of covers on all connection points to reduce faults caused by nesting birds and other foreign objects carried by the wind; installation of new transformers filled with biodegradable fluid that has a higher flash point to reduce equipment failure; installation of surge arresters that allow the electrical system to operate without producing sparks; and installation of fast-acting, current-limiting fuses that interrupt electrical flow if a fault is predicted to reduce energy output.

Additionally, PAR has installed automated overhead switches, also known as remote-controlled automatic reclosers, that sense overload on lines and can automatically shut power off to achieve public safety power shutoffs. These devices also divide circuits into segments to minimize customer impact.

SCE pioneered an early fault detection system that uses antennas sitting atop utility poles to listen for abnormal sounds related to unusual circuit activity. The system detected a fault near an elementary school in Murrieta, Calif., which otherwise would have gone unnoticed. It turned out to be damage from a .308 Winchester rifle, later confirmed through lab analysis of compromised lines.

Tree trimming

Among the most important efforts to control circuit activity caused by faults and interference is tree trimming. 

“There’s been a huge effort to trim trees and clear away brush, which irritates customers, but it has to be done,” Stapp said.

PAR is not involved in tree trimming, yet Stapp and other line contractors are well aware of the need to control vegetation, and they anticipate efforts will intensify. 

“The rains and heavy snowfalls of 2023 are fueling a resurgence of plant growth here,” Stapp said.

SCE’s current goals and objectives indicate that plenty more hardening work must be accomplished. The utility’s new 2023–2025 Wildfire Mitigation Plan prioritizes installation of covered conductor in areas at high risk for wildfire and public safety power shutoffs. By 2025, SCE expects to replace an additional 2,850 miles. SCE also expects to complete 100 miles of undergrounding to address high-risk communities with roads offering only limited entry and exit points.

Undergrounding

Other utilities are also embracing undergrounding as a solution to limiting fire potential.

In response to a tree falling on one of its power lines and sparking the 2021 Dixie Fire, which destroyed 1 million acres, PG&E’s CEO Patricia Poppe announced the company’s ambitious plan to bury 10,000 miles of line.

“This is an extraordinary problem,” Poppe said, adding that the expected cost would amount to $3.75 million per mile.

PG&E serves more than 16 million people across 70,000 square miles in northern and central California. The company’s online videos reveal the undergrounding process as arduous and often requiring digging up roadways and repaving.

PG&E set an undergrounding goal of 350 miles for 2023—an indication the process could span decades. Buried cable does not spell the end for utility poles, because homeowners and businesses still want service and are not necessarily willing to foot the expense for burying distribution lines.

Utilities also have invested heavily in weather monitoring technology to be able to predict high-risk climate conditions and anticipate when shutoffs may be needed. Since 2018, SCE has installed 1,620 weather stations.

PAR has installed a new generation of current-limiting fuses for SCE, though it has not been involved in efforts to bury transmission lines or install weather stations.

SCE and other utilities have also stepped up equipment inspections. Since 2018, the utility has conducted more than 1 million inspections in areas with a high risk of fire, thanks to drone technology. 

“Mostly, the utility does the troubleshooting,” Stapp said. “Once they resolve it, they call us in, and we put things back in order.”

SCE has also provided eligible residential customers, mostly those with medical needs, with 10,200 backup batteries since July 2020. Other utilities are constructing large backup battery systems to keep power flowing to essential emergency services and medical providers.

Much like SCE, San Diego Gas & Electric’s 2022 Wildfire Mitigation Plan pushed the company forward in its system-hardening efforts. Since 2020, the utility has undergrounded more than 70 miles of overhead infrastructure, hardened more than 430 miles of overhead power lines, replaced wooden poles with steel ones, upgraded more than 40 miles of power lines with covered wires and deployed falling conductor protection technology, which de-energizes power lines before they strike the ground.

Last April, San Diego Gas & Electric applied to the U.S. Department of Energy, seeking $100 million in federal funds through the Grid Resilience and Innovation Partnerships Program, a subprogram of the federal Infrastructure Investment and Jobs Act.

Such a grant could offset the costs of wildfire hardening efforts on and around federally recognized Tribal Land within the utility’s service territory. Pending approval from CPUC, San Diego Gas & Electric could commit up to an additional $100 million in matching funds for grid hardening efforts. Funding cycles would start in 2024.

About The Author

DeGrane is a Chicago-based freelance writer. She has covered electrical contracting, renewable energy, senior living and other industries with articles published in the Chicago Tribune, New York Times and trade publications. Reach her at [email protected].

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