Development and Application of Leakage Current Monitoring Device of MOV in UHV/EHV Series Capacitors

According to the working characteristics of Metal Oxide Varistor (MOV) in series capacitors, the architecture of MOV's leakage current monitoring device using for EHV or UHV series capacitors was studied in this paper. The method of extracting and correcting resistive current of each MOV based on main capacitor current was proposed. Furtherly the MOV's leakage current monitoring device and power supply based on current transformer was developed. The finite element model of the series capacitors was established and the electric field intensity and potential distribution after installing the monitoring device were simulated and analyzed. The application of MOV monitoring device was firstly implemented in China, and the leakage current data of under MOV's operation were obtained, which provides reference for the development of condition monitoring technology of series capacitors in the future.