AC electric characteristics of 110 kV post insulators covered with ice or snow

We studied the AC electric characteristics of 110 kV post insulators covered with ice or snow, compared the anti-flashover function of adding creepage extenders and permanent-room-temperature-vulcanized anti-contamination flashover composite coating(PRTV), analyzed the influence of weight and thickness of ice on icing flashover performance of 110 kV post insulators covered with ice, and put forward the equivalent relation between them according to the equivalent principle to the flashover voltage of iced-covered composite insulators and the measures of improving the icing flashover voltage of 110 kV post insulator. The tests show that the flashover voltage can increase fifty percent for the post insulator of adding creepage extenders, there is no positive effect of PRTV on severe icing process. Compared with the post insulator string which is not coated with PRTV, the relation between m and d is m=4.7lnd-8.8. The results can offer some consult for the external insulation selection and design of transmission lines at ice region.