Switching Surge Flashover of UHV Transmission Line Insulation

The switching-surge performance of a large number of basic uhv transmission line insulation configurations has been extensively studied. The paper reports on outside phase, tower window, conductor- to-ground (with and without protrusions), conductor-to-conductor, vertical and horizontal rod-rod and rod-plane gaps. The investigated air gaps range from 10 to 66 ft (3.0 to 20.1 m) and the associated switching-surge strengths range from 1100 to 2700 kV. The paper extends earlier work1 and offers numerous design curves to the transmission line designer for uhv transmission systems up to 1500-kV system voltage.