A new analysis of the composite insulator flashover

The composite insulator is a kind of new insulator developed in the mid 1960s. The faults of the composite insulator have been divided into three kinds including bird streamer flashover, lightning flashover and contamination flashover. The bird streamer is the main fault source that happens during the dynamic defecation processing of birds at dawn. But on the basis of experiments, it is proved that some flashover at dawn is due to the uniform distribution voltage. The dry high voltage part of the composite insulator bears relatively high voltage. When salt solution with different concentration, equal to different parallel resistance, was imbrued on the composite surface nearest to the power line, the distributed voltage of the whole composite insulator would change. The voltages of sheds near the power line increase more than the others. Therefore long-term effect under such conditions induces partial flashover, even power fault. Finally it is suggested that the high voltage part of the composite insulator should be improved.