Research On Insulation Performance Of Outdoor Insulator Under The Condition Of Snow-Ice Covering

A lot of observation and reports in the world indicated that flashover voltage of insulator covered with snow or ice descended obviously. On the condition of insulator covered in snow or ice chill climate area of northeast in China, many accidence of insulation flashover occurred which brought prodigious damage for electric power system and loss for economic. To this question, the item of the study of characteristic of insulator covered with snow of ice was brought by Liaoning province electricity board. This paper investigated AC flashover performance of insulators covered with snow or ice condition in tow ways of theory and test analysis.On the theory analysis, the post insulator structure is divided to triangle cell and electric field distribution including cleanness and covered with snow or ice etc is calculated by finite element method using FORTRAN language. Then the results are analyzed and the point of max electric strength was found. The electric field distributions of cleanness and covered with snow, the electric field variety of covered with ice, and the break down electric strength of covered with snow and ice were analyzed. The affect of the angle of medium loss for insulation performance was analyzed.On the test investigation, a lot of flashover tests are made in 10kV, 35kV and 63kV voltage condition on post insulators and suspensor insulators, including all conditions covered with snow or ice. Which included different environment temperature, different melted ice and melted snow etc multi-condition. The paper studied withstand voltage level, influence factors, breakdown process and breakdown mechanism of covered with snow or ice through some theory calculation results, many test data and phenomena. The paper got the conclusions that withstand voltage strength of insulator covered with snowor ice descended largely, and the amount of ice or snow build-up, number of flashover, string length, environment temperature and leak current etc had obvious effects on flashover voltage values of insulators.At the last, this paper brought forward advice to improve insulation level and ability and advised several problems needed research in detail future.