Study on pollution flashover characteristic of insulators on 500 kV AC transmission lines in high-altitude area

Pollution flashover performance of insulators is one of the key factors to be considered in the selection of external insulation for transmission lines at high-altitude areas. In pollution laboratories at Tibet high-altitude test base and Beijing ultra high voltage direct current (UHVDC) test base, artificial pollution tests of insulators adopted in AC 500 kV transmission project are performed both in sea-level region and real high-altitude regions, through which flashover voltages at typical equivalent salt deposit density are obtained. The relationship between altitude and flashover voltage is acquired as well.