Study on the icing flashover characteristics of porcelain double sheds suspension insulator string

In the present paper, study on icing flashover characteristics were carried out in artificial climate chamber of State Grid Electric Power Research Institute (SGEPRI) with XWP₂-160 porcelain double sheds suspension insulators. According to IEEE Task Force on insulator icing test methods the natural freezing rain condition was simulated and 3 to 7 units XWP₂-160 insulators were icing energized at service voltage. Based on the tests results, the U_50% increases with an increase in dry arcing distance linearly for XWP₂-160 not more than 7 units. The effect on icing flashover performance of the factors such as ice thickness and applied water conductivity were investigated respectively. More over, ice states and discharge process of insulators icing energized were compared with the de-energized ones and discussed. For the air gaps can enhance the electrical strength of iced insulators, the U_50% withstand voltage of insulators icing energized is higher than the de-energized ones.