Three cities go dark in early morning power outage

The cities of Wrangell, Petersburg, and Ketchikan all suffered a power outage in the early morning of July 4. Rod Rhoades, light and power

director for Wrangell, said that the outage hit Wrangell at 3:05 a.m., but started in Ketchikan.

All three communities are connected via the Southeast Alaska Power Agency, meaning they receive and share power from the same sources. While power has been restored, officials are still looking into the cause of the outage.

All three cities lost power around 3 a.m. Roades said that Wrangell switched over to diesel power at approximately 4 a.m., and SEAPA power was fully restored by 7 a.m. on the morning of July 4. Rhoades said his understanding was a bird strike knocked out the power grid in Ketchikan, which made Wrangell and Petersburg also lose power.

Jeremy Bynum, electric system engineering manager with KPU, said they also assume a bird was responsible for a power outage. They cannot confirm this, he said, but there was no lightning strike or equipment failure to point to. Bynum also said that there were several factors that played a part in power being lost in all three SEAPA communities, such as where the outage specifically began and the time of day, when few generators were running.

Around 3:01 a.m., Bynum said, there was a phase fault on a power distribution line between the Bailey and Ketchikan substations, where it is assumed a bird or small animal struck the line. This caused Ketchikan to separate from SEAPA's power generation, he said. This cascaded to create "over frequency conditions" at Tyee Lake, where SEAPA primarily generates power for Wrangell and Petersburg. Over frequency conditions, Bynum said, are when more power is being generated than the load needs at the time. These conditions then tripped off the generator at Tyee Lake, which knocked out the power to Wrangell and Petersburg.

Bynum said that they got all of the systems tied back together around 8 a.m. on July 4. An internal review and an after action report will be organized, he said. They will be looking at the process of what happened and Ketchikan's response to the blackout. An outage report will be submitted to the Ketchikan city manager in the near future, he said.