Experimental study on the pollution flashover mechanism of polymer insulators

For an extensive understanding of the pollution flashover mechanism on hydrophobic surfaces, a series of experiments were designed to investigate the relationship between hydrophobicity, pollution severity and pollution withstand property of polymer insulators. Rain tests with the conductivity 100 /spl mu/S/cm to 100000 /spl mu/S/cm were conducted on the silicone rubber insulators presenting various hydrophobicity statuses. It is found that the electric conductivity and accumulating status of water droplets or zones on the hydrophobic surface is tied closely to the sequence flashover voltage, even in the case of complete hydrophobicity. The accumulating status and the conductivity of water droplets on the contaminated polymer insulators depend both on the hydrophobicity and on the pollution severity. It suggests that the pollution flashover voltage on the hydrophobic surface relates not only to the hydrophobicity but also to the pollution severity. Based on the results, pollution flashover mechanism on the hydrophobic surface is discussed.