Research on Leakage Current Characteristics and Thermal Process of Gradient Valve Plates under High Frequency Voltage Conditions

Aiming at the roof arrester fault caused by high-frequency overvoltage during the operation of high-speed EMU, combined with the high-order harmonic overvoltage characteristics during the operation of EMU, the high-frequency and high-voltage test of arrester gradient valve plate is established. The leakage current characteristics of valve plate are obtained, and the active power of valve plate with different size parameters are compared. The results show that the leakage current of arrester valve increases linearly with the increase of voltage and frequency, and increases with the increase of valve radius. The leakage current of gradient valve is obviously smaller than that of ordinary valve. In terms of heating, the electric heating distribution of gradient valve plate is more uniform. The research provides a basis for the selection of roof arrester under complex overvoltage conditions.