Fault Analysis of Zinc Oxide Surge Arresters Based on Infrared Thermal Imaging and Resistive Leakage Current Detection Method

Zinc oxide surge arresters are widely used in overvoltage protection due to their excellent nonlinear voltampere characteristics and current-carrying capabilities. However, long-term operation may lead to defects such as heating and a decrease in insulation capacity, posing a threat to the safe and stable operation of the power system. This paper addresses the infrared temperature measurement and abnormal full-current online data phenomenon discovered during temperature inspections at a 220kV substation. Through live and power-off tests on zinc oxide surge arresters, the degradation of the internal resistor elements is preliminarily determined, indicating a potential insulation fault. Further dismantling analysis reveals that the sealing rubber ring of the surge arrester has aged, resulting in loss of sealing effectiveness. This causes the zinc oxide valve elements of the surge arrester to be dampened, leading to a loss of its inherent nonlinear volt-ampere characteristics. In response, preventive measures such as strengthening the operation and maintenance of similar equipment are proposed to provide technical support for the safe operation of surge arresters. The comprehensive fault diagnostic method can serve as a reference for analyzing abnormal operation data of surge arresters.