Study on AC pollution flashover performance of cap-and-pin and rod insulators at high-altitude sites

The external insulation of electrical equipments is affected by the atmospheric parameters in high-altitude regions. However, there is a lack of studies conducted at the high-altitude sites of 3000 m and above worldwide so far, in contrast to many fruitful ones carried out in the artificial climate chamber. The authors investigate AC pollution flashover performance of cap-and-pin and rod insulators at high-altitude sites with a view to bridging the gap and enriching our understanding in the aspect. The AC artificial pollution tests are conducted at three high-altitude sites of 2820, 3575 and 4484 m, respectively. The results show that the exponents characterising the influence of salt deposit density, non-soluble deposit density and air pressure are 0.297–0.352, 0.122–0.142, 0.535–0.580, respectively; ambient temperature has an obvious effect on the pollution flashover voltages; there is no obvious relation between the insulator profiles and the influence exponents of salt deposit density, non-soluble deposit density, air pressure or ambient temperature.