Research of Metal Oxide Arrester on-line Monitoring System

Metal oxide arrester (MOA) is an important overvoltage protection device. However, some MOA will deteriorate gradually under operating voltage, and some will get wet due to structural problems. These two failures can lead to increased leakage current in the arresters, and accidents can happen even when the power system is severe. The first harmonic current and high harmonic current of the resistance are two fault eigenvectors reflecting the MOA performance. According to the characteristics and requirements of the measurement of conductive leakage current, this paper puts forward the principle and realization of the insulation on-line monitoring, and chooses to monitor the harmonic analysis of the conductive leakage current. The paper uses digital processing programming to obtain the resistance leakage current by virtual instrument, and then obtains the resistance wave current and harmonic current. Based on Lab View, the design of the entire MOA insulation monitoring system is also finished, including the system hardware and monitoring software. The on-line monitoring system of MOA can detect and monitor the resistive leakage current and harmonic resistive currents in good condition.