Leakage Current Pattern for Diagnosing the Contaminated Degree of Ceramic Insulators under Different Humidity

In this paper, leakage current flowing along contaminated ceramic insulators was separated into low frequency component and pulse component, which were detected respectively by Rogowski coil in artificial contamination tests. The effects of the operating voltage, the equivalent salt deposit density and humidity on the two characteristic components of leakage current were investigated. It is revealed that the peak of the pulse current component has a sudden rising during the increase of humidity, and the inflexion has been found to be closely related with the low frequency current. The diagnosing methods based on the combination of the two current components have been proposed eventually.