Power outage caused by aging infrastructure

Heralding the onset of winter, power went out across swaths of Wrangell the afternoon of Dec. 17 after a distribution feeder failed.

At around 3:15 p.m. Feeder 1 near the Public Works yard went down, affecting distribution to much of Church and Cassiar streets, Evergreen Avenue and Spur Road. Power to Wrangell Airport’s runway lights was also cut out, though fortunately after a plane had already landed.

“There were certainly some concerns to be had there,” commented Municipal Light and Power superintendent Clay Hammer. Residents elsewhere in town may have noticed a flickering in their power through the afternoon.

“It kind of caught us by surprise a little bit,” he said of the outage. The annunciator connected to the system flagged the problem as “A-phase to ground,” which Hammer explained generally signifies a tree fallen on the line somewhere. Occasionally it can indicate a failed insulator and even more rarely a bird strike.

A search along the transmission lines failed to find an obvious fault.

“We knew where the problem kind of was,” Hammer recalled. Narrowing things down, the department found the problem was actually with the underground conductors, about six feet from the feeder.

“That wasn’t something we were prepared to fix really quickly,” Hammer said. The department then used some “creative backfeeding” to restore power through Feeders 2 and 3 by about 5 p.m.

“We’ve not had one of those happen like this before,” he continued. “Not that we weren’t concerned about it.”

The outage happened to coincide with an electric rate workshop scheduled between the local utility and Borough Assembly. Toward the top of a list of items identified for overhaul or replacement by this year’s system’s study were the riser conductors, which Hammer said are approaching 35 years in age.

“They’re due. It’s time to replace them,” he said.

Released in June, the system study found that many of the borough’s utility poles have passed their life expectancy. Half are more than 40 years old, and an additional 30 percent of poles are over 30 years old. A fair number of poles in the distribution system are also overburdened by telecommunication lines.

In addition to power poles, transformers and streetlights would need to be reinstalled and the primary conductor replaced. In all, the study anticipates the cost to make the necessary fixes may be up to $340,000.

Given the overall age of the system and increasing usage, Hammer said things

were bound to fail at some point. What was worrying about this month’s outage was the load was not particularly high. He pointed out the outage “backed up the assertion we probably need to get on that pretty soon.”

The problem has been temporarily fixed, but excavation work will be needed for a more permanent solution. He expects work to replace the failed

conductor will be done this summer, using a portion of this year’s Southeast Alaska

Power Agency rebate to fund the fix.

First though, Hammer said he needs to put forward a spending plan to the Assembly at its January or February meeting. The risk of something similar happening again this winter is “certainly there,” but he felt the department could back-feed power again in a shorter time, if necessary.