Cause of summer power outage determined

Rocky Mountain Power has determined what was responsible for a regional power outage on July 19, 2016. The outage affected an estimated 100,000 customers.

Spokesman Dave Eskelsen said two crows came into contact with a capacitor bank at the Goshen Substation. The birds created an electrical fault that caused a brief fire. But, he said the real cause of the outage was a protective relay, or a high-speed electrical switch, that failed.

Since the outage, Eskelsen said PacifiCorp engineers have modified that relay to make sure this kind of problem doesn’t happen again.

He said the work was part of several corrections made in the past couple of years, including a redesign of the way the substation works. The utility has also made improvements in design and capacity aimed at addressing distribution problems.

While electricity to Rocky Mountain Power and Idaho Falls Power customers was restored within two hours, it did take longer for some customers served by Fall River and Lower Valley Energy. Eskelsen said that was due to technical issues involved with protecting distribution systems while power was brought back on line.