Pollution flashover performance is one of the key issues of external insulation selection of transmission lines. Researches nowadays focus more on influence of salt/non-soluble deposit density on flashover performance. Influence of salinity of salt fog on flashover performance is not paid attention to. However

the impact of salt fog on insulator flashover cannot be ignored according to the flashover accidents happened in Hainan power grid. Therefore

we simulated the contaminated insulators flashover in salt fog in artificial pollution chamber

and obtained the pollution flashover voltages of three types of insulators under different salt deposit density and salinity. And flashover voltages were fitted to formula as well. The analyses of test results show that the relationship between pollution flashover voltage and salt deposit density is a power function even in salt fog. With the increase of salinity of salt fog

pollution flashover voltage decreases. The relationship between them is a power function as well.