In view of the air pollution causes the fog water conductivity to increase

the pollution flashover probabili-ty of composite insulators is also increased. Put forward salt fog method to study composite insulator pollution flash-over characteristics. In the artificial fog and haze simulation experiment box

through controlling the fog water con-ductivity and fog water content

and using uniform boosting method

a large number of tests are carried out on the in-sulator by two steps of vapor mist generation and dissipation

meanwhile flashover voltage are recorded and the flash-over path is observed by using high speed video camera. The results show that when the fog water content is low in theair

the fog water conductivity has no obvious effect on the insulator flashover voltage. With the fog water content in-creased

the effect of fog water conductivity on insulator flashover voltage is obvious and the clean composite insulatorhas a higher probability of arcing and flashover at its injection marks

and it has little effect on the polluted insulator.