Effect of vertical electric field components on the local arc development along contaminated surfaces

Abstract During operation, a vertical-component electric field emerges on the surface of high-voltage AC bushings. This unique electric field structure renders the bushing more susceptible to discharge and flashover. However, limited attention has been paid to studying the flashover characteristics resulting from surface pollution in such electric fields. This investigation, involving four differently structured bushings as well as post insulators, delves into the impact of pollution, creepage distance, and electric field structure on bushing flashover characteristics. The study reveals that increasing the creepage length of heavily polluted bushings does not significantly enhance their flashover voltage. Moreover, the role of the vertical electric field in the local arc development was analysed. This research could provide valuable references for future bushing design in polluted areas.