Effect analysis of local umbrella skirt edge defects of high-speed train roof epoxy resin insulator on the electric field distribution characteristics

The epoxy resin insulators on the roof of high-speed train work in an outdoor environment for a long time, and the aging umbrella skirt edge will form a gap when it is hit by a hard object, and the broken umbrella skirt will reduce the creepage distance, which may induce a flashover fault and even cause the train power supply interruption. A model including defect location, defect shape and radial defect depth was constructed and its potential distribution was calculated. Calculation results show that, with the constant defect shape and defect area, the local electric field strength distortion is the largest when the defect location is in the first umbrella skirt at the high-voltage end; the local electric field strength distortion rate is higher than that of the crescent-shaped defect with the shape of the broken area being triangular with the defect location and defect area in constant. When the defect location and shape are in constant, the decrease in creepage distance and the distortion rate of electric field strength increase with the increase of radial depth of the defect. The calculation results can provide a reference for evaluating the influence of insulator defects on the electric field distribution.