Observation of Flashover Process of 33 kV Long-rod Insulator during Artificial Snowstorm

This paper presents the AC flashover process of a snow-bridged long-rod insulator used for 33 kV overhead lines in the presence of a salt contaminated snowstorm in a climatic chamber. The severity of the snowstorm was defined as having snow conductivity up to approximately 1,000 ?S/cm, 10 m/s of wind velocity, and 9.2 g/m3 of mass density of drifting snow. Leakage current waveforms under constant voltage stress were monitored. Visual observations of discharge propagation were also carried out by using a high-speed camera simultaneously with the leakage current measurement. The results showed that a spark-like partial discharge appeared at the snow gaps during the initial cycle of sequent current waves before flashover. Then the spark-like discharge bridged a gap between the insulator sheds…