Southern California Edison customers on the Tapo circuit in Simi Valley experienced four Public Safety Power Shutoffs between last November and December, affecting some, if not most, of the 1,374 customers on the circuit each time.
Under similar weather conditions and with the expedited grid hardening that SCE has initiated and targeted for completion by Oct. 1, before peak wildfire season, none of the PSPS outages likely would have occurred.
And the good news for customers is that it’s only one of more than 60 cities and unincorporated communities in high fire risk areas, ranging from Santa Clarita to Malibu to Fontana, that should see a sharp reduction in the impacts of PSPS when SCE’s expedited upgrades are completed on the most frequently impacted circuits. The work will also increase reliability in general.
Terry Ohanian, SCE’s director of grid hardening, and the utility’s PSPS Readiness Team are laser focused on the PSPS Action Plan to decrease the need for PSPS, a tool used as a last resort to protect public safety under dangerous weather conditions.
“We want to reduce the number of PSPS events, reduce the duration of PSPS events and reduce the number of customers who experience PSPS events,” said Ohanian, a 31-year SCE veteran and frequent incident commander on the utility’s PSPS Incident Management Teams. “It’s good news for our customers affected by PSPS.”
A deep-dive review of the areas most impacted by PSPS -- or those with four or more PSPS de-energizations since 2019 -- resulted in circuits feeding 80,000 customers being targeted for expedited grid hardening. This work was originally scheduled for completion at the end of this year and next year, but will now be completed by October.
For starters, one-third of the approximately 700 miles of bare power lines previously scheduled to be replaced with insulated lines, or covered conductor, will be expedited along with at least 70 miles of new work. This will help eliminate the risk of an ignition when a tree branch or other debris blows into equipment during high winds and reduce the need for PSPS.
In addition, SCE will automate 18 remote-controlled switches and install seven new switches to allow more precision and de-energize smaller areas, install nine new weather stations and improve protocols to switch customers to nearby circuits unaffected by a shutoff, when possible.
“When we complete work on these circuits, we are currently estimating a 78 percent reduction in PSPS on them under weather conditions similar to last year,” said Ohanian of SCE’s backcast method that analyzed past weather conditions against the expedited upgrades. “This means that while 57,000 customers on these circuits experienced at least one PSPS outage last year, about 37,000 of these customers would not have experienced an outage after the expedited upgrades and, of the remaining 20,000, many of those would have seen fewer and/or shorter PSPS outages.”
The replacement of bare wires with insulated wires is a big part of this improvement, making blowing debris less problematic and allowing higher thresholds for wind speeds, among the key triggers for PSPS.
The remote-controlled switches and weather stations are no less important to reducing PSPS.
“If you think there’s a portion of the circuit that’s really a concern, but you’re impacting a larger number of customers by de-energizing the entire circuit, then installing the sectionalizing device switch along with the weather stations gives you the ability to hone in on just that area,” said Ohanian. “It gives you the ability to not de-energize customers you don’t have to.”
For customers, however, who question why their power is cut off when they receive their electricity from underground lines or why neighbors directly across the street have power when they don’t, they can still experience PSPS because they’re fed by overhead lines that cross high fire risk areas. Even those customers, however, should see fewer PSPS when wind thresholds are raised after covered conductor is installed on the source feed line.
These expedited upgrades will create short-term maintenance outages that SCE will do its best to minimize during this critical work.
“This work just really matters,” said Ohanian. “There are customers at the end of every decision, and we have an obligation to get this work done.”
A determination echoed by the PSPS Readiness Team’s leader.
“We do not take lightly the use of PSPS to mitigate wildfire risk and we appreciate our communities’ patience as we accelerate our grid hardening to reduce the customer impact of PSPS,” said Erik Takayesu, SCE’s vice president of PSPS Readiness. “We understand that 2020 was particularly difficult and we have heard clearly from customers, regulators, government officials and public safety partners that we must reduce the need for PSPS.”
(Paul Netter is an "Energized by Edison" writer for Southern California Edison.)