Thousands of homes and businesses were without power for about an hour in Anchorage and the Mat-Su on Monday evening, in a widespread outage.
The outage initially knocked out power for more than than 45,000 members in Anchorage, and more than 19,000 customers in the Matanuska-Susitna Borough. Utilities in both regions said later Monday evening that they had largely resolved the issue and restored power to most homes and businesses.
Both Chugach Electric and Matanuska Electric Association said in posts to social media that the utilities had experienced a large “load shedding” event.
“It appears this is a load shedding event which happens when a major source of generation is lost somewhere on the Railbelt,” Chugach Electric said in its post.
“What we know is there was a fault on the transmission line about 10 miles north of the Teeland Substation near Wasilla,” the statement continued. “... The fault caused an under-frequency event that in turn caused two Chugach generators to trip off line, which then triggered the load shedding event.”
The utility said the issue could have been caused by a fallen tree or something else, and that crews were patrolling the area on Monday to find the exact cause.
Similarly, MEA posted that the utility experienced an outage triggered by “a fault on the northern inner tie causing two Chugach generation units to go down.”
“We currently have crews patrolling the inner tie to determine if there are any additional issues or hazards before the transmission line is re-energized,” the utility said in an update.