Experimental investigation on flashover performance of glass insulator for DC transmission lines at high altitudes

This paper presents the results of an investigation on the DC flashover characteristic of contaminated glass insulators at natural high altitudes (1970 m). The arcing behavior on natural contaminated glass insulator surfaces was studied using a high-speed camera. The experimental results show that the DC arcs have a significant influence on the flashover performance of contaminated glass insulator since the DC arcs levitate more easily from the insulator surfaces at high altitudes than at sea level. The insulator profiles, contamination distribution condition, and suspension patterns (I- and V-strings) have a strong effect on the arc behaviors resulting in an obvious difference for the utilization ratio of leakage distance of the glass insulator, and this has a strong influence on the flashover voltages.