Analysis on Causes of an Arrester Anomaly Based on Electric-Temperature Field Simulation

This paper, through the infrared precise temperature measurement special electric live detection carried out during the electricity consumption peak of winter season in the substation under the jurisdiction of a power supply company, found that the temperature of the B-phase arrester on the 35 kV side of a 110 kV main substation was abnormal and the leakage current was much higher than those of the other two phases. After power outage, electrical test was conducted. Through disassembly inspection, it was found that the surface of the aluminum strutting piece in the phase arrester was oxidized and there was obvious traces of water and other abnormalities. After disassembly of the abnormal valve piece, pressurization and infrared temperature measurement test were carried out which found at least 6 pieces of the 13 pieces valve piece in the arrester were deteriorated. Through the electric field simulation, it was found that if there is a gap, it will generate an impact on the electric field at the entrance of the lug of the arrester but does not affect the overall electric potential distribution of the arrester. While through the electric - temperature field simulation, it was found that under normal circumstances, the overall temperature distribution of the arrester is more uniform; the temperature distribution of the arrester under moisture is not uniform in which case the resistivity of the faulty valve piece is reduced. Its temperature is lower than the normal valve piece, and the overall resistance of the arrester would be reduced, thus driving an increase in current and temperature.