Squirrel causes large power outage, closing South Portland, Peaks Island schools The disruption occurred in a substation on Highland Avenue in South Portland, according to Central Maine Power Co. Share A squirrel caused a disruption in a South Portland substation that knocked out power to thousands of customers and closed schools in South Portland and on Peaks Island on Thursday. The outage impacted more than 5,300 customers in South Portland, 200 customers in Cape Elizabeth and 1,400 customers in Portland early Thursday morning. Power was restored by around 11 a.m. after repairs were made at the Central Maine Power substation on Highland Avenue.