Xcel Energy says it will be using helicopters to inspect more than 7,000 miles of high-voltage transmission lines in the Upper Midwest over the next month. The utility says the work is part of federal regulatory compliance requirements for U-S energy providers. Crews working in Wisconsin will initially focus on lines north of Eau Claire to Michigan’s Upper Peninsula. Then, they will work between Eau Claire and La Crosse. Crews will be looking for line or structural issues, plus possible conflicts between buildings or vegetative growth and those lines. In some cases, the helicopters will fly within 50 feet of the transmission lines at varying speeds.