Study on the Critical Conditions of the Insulator String Covered with Ice Based on the Leakage Current

The research is focused on the growing trend of the leakage current (LC), of a porcelain suspension insulator during the flashover progress in different ice parameters with a glaze ice accretion. The result shows that, by the difference of the LC growing trend, the flashover progress on the ice accreted without voltage could be divided into four components including the weight of ice accretion, the ESDD on insulator surface, the number of unit per insulator string and the water conductivity for icing, which were corresponding to the flashover phenomenon. Two kind of LC (IW and IFT) were defined to study the relationship between LC and flashover in different ice parameters. In the condition of ice satura-tion, those two indexes are just sensitive to the water conductivity for icing while…