A Method for Calculating the Growth Rate of Resistive Current and Fault Diagnosis of MOA Based on Synthetic Vector

At present, metal zinc oxide arresters are used for station-type arresters with voltage levels of 110 kV and above. The stability of the arrester valve plate mainly depends on the monitoring of resistive leakage current. Resistive leakage current is sensitive to the initial aging, moisture, and other reactions of the valve plate. The interference of phase capacitance is the most important factor to measure the resistive current of arrester. In order to solve the problem of low proportion of resistance current component in leakage current and difficulty in measurement in traditional MOA detection methods, this paper synthesizes the vector of the total leakage current of the three phases, and indirectly obtains the growth rate of the resistive current amplitude through the variation of the synthesized vector phase angle. Through sample testing, this method can effectively remove the influence of inter phase coupling capacitance and has greater stability to ensure the correctness of resistive leakage current calculation, thus truly reflecting the operating status of the lightning arrester.