AC withstand voltage characteristics of insulator string covered with snow

Results of an investigation into the withstand voltage characteristics of a UHV-class tension insulator string covered with snow are reported. AC withstand voltage tests were conducted in a testing room and at an exposure testing station constructed in a heavy snow area. For insulator strings up to 10 m long, the withstand voltage was almost roughly proportional to the length of the insulator string. The relations between the withstand voltage and the characteristics of the snow are reported. A design example for determining the length of the snow-covered string is presented