BPA on June 21 implemented its first-ever public-safety power shut-off (PSPS) under a new policy adopted earlier this month, targeting a south-central Oregon line segment in response to forecasted strong thunderstorms and high winds, the agency told Clearing Up.
The event was initiated at 6 p.m. with the de-energization of a segment of the Brasada-Harney 115 kV No. 1 line, which runs southeast from about 10 miles east of Bend to the Harney substation about 5 miles southwest of Burns.
The shutdown impacted the Harney and Central electric cooperatives, as well as the Riley, Starvation, Suntex and West Hines solar projects.
Although weather forecasts indicated the shutdown should stay in place for 13 hours, until 7 a.m. the next day, Bonneville meteorology staff determined a second round of thunderstorms wouldn't pose a threat, and so it was terminated after nearly 5 1/2 hours, at 11:22 p.m.
Bonneville views a PSPS as a last-resort measure for the "worst case" situation, and in view of recent historic wildfires in the region adopted an official policy June 1. To help make the decision to activate it, BPA assembles a decision-making team during extreme risk days, in cooperation with the U.S. Forest Service. The agency's Transmission Operations group has the sole authority on whether to activate a shutdown.
Michelle Cathcart, VP of BPA Transmission System Operations, said the National Weather Service had already declared a red flag warning that warm temperatures, very low humidities and stronger winds were expected to combine to produce an increased risk of fire danger in the area.
When an alert went out from Transmission at 1:43 p.m. that winds of at least 60 mph were expected later that day, a decision-making team of BPA subject matter experts convened within the hour to talk through the situation and come up with a list of potential high risks.
The team reconvened at 3:30 p.m. after gathering more information on customer impacts and further analysis of at-risk facilities, and made a decision within 30 minutes to initiate a shutdown at 6 p.m. of the Brasada-Harney segment of most concern.
While the PSPS generally proceeded as planned, Cathcart said it was complicated by the short notice they were able to give customers.
"The alert came up quickly," she said. "We want to give 24-48 hours' notice, but here we activated on shorter notice. Even so, vegetation, operations, meteorology [subject matter experts] were able to come to the best solution for the region."
In the run-up to the shutdown, Bonneville operations and dispatch personnel started having operational communications with the affected utilities through normal channels at about 2 p.m., and Transmission customer account executives reached out to retail utility customers and regional stakeholders through calls and emails about a half-hour later.
The consensus of the "after action" meeting held to discuss the PSPS was that "ideally, we would have given more notice, but given specifics of weather coming up so quickly, we did as well as we could," Cathcart said.
Meanwhile, Avista said June 25 it had responded to dry summer conditions and increasing wildfire danger by adopting a temporary measure for power line operations in its Washington and Idaho service areas.
In a news release, the utility said the aim of the measure—called the dry-land mode—is to decrease wildfire potential while re-energizing power lines. Normally re-energizing is an automated process, but during the current dry conditions, Avista's line personnel will physically patrol an outage area before placing a line back into service.
"This can require more time to restore service, but decreases the potential fire danger," the utility said.
Avista says it is expanding dry-land mode this year by pairing it with a fire-weather monitoring system that allows system operators and field managers to make better-informed decisions on a more targeted geographic basis.
The utility said it will return the distribution system to normal as soon as weather permits and fire potential decreases.
In a presentation to Washington regulators in late May, Dave James, Avista's wildfire resiliency plan manager, said the process it has in place should be enough to reduce the risks, and that "public-safety power shut-off is not in our toolkit."