AC Pollution Flashover Characteristics of Post Insulators Under Low Air Pressure

At high altitude, the external insulation safety of the electrified railway is threatened by low air pressure, pollution and other harsh factors. In order to inform the reasonable choice of external insulation for electrified railways at high altitude, this paper takes post insulator QBG-25/16 (2000) as the research object, simulates different air pressure and pollution situations, and studies AC flashover characteristics of pollution post insulator under low air pressure. The research shows the flashover voltage of post insulators decreases in a power function as the air pressure decreases as well as the pollution of the surface increases. The air pressure influence characteristic index of the flashover voltage of pollution post insulators is 0.456~0.610, and the pollution influence characteristic index of the flashover voltage of pollution post insulators is 0.377~0.432. In addition, the altitude correction of post insulators is also proposed. The results give a technical reference for insulation coordination of external insulation of electrified railway at high altitude.