The Self-powered Monitoring System of Resistive Current for Line Type Metal Oxide Arrester

The resistive current of metal oxide arrester (MOA) can be used to characterize the state of the arrester. However, it is difficult to accurately obtain the line voltage and monitor the energy supply of the device when the resistive current of the wire is extracted by the fundamental wave method. In this paper, a self-powered monitoring system for the resistive current of a wire-type arrestor is proposed. Based on the theory of dielectric and electrostatic induction, a passive voltage measurement device for the line MOA is designed by quantifying the partial and induced voltages of the induction plate below the line. Considering the microcurrent characteristics and interference, a measuring circuit with amplifying and filtering functions is designed to achieve the full current measurement with a minimum of 500 μA. According to the charge-discharge characteristics of capacitor and the energy conservation relationship, a micro-current energy extraction circuit is designed, which can supply more than 1.1 mW of energy to the system at 500 μA current. The experiments at 14 kV voltage verifies that the system can run on the extracted energy, and extract μA class resistance current of the 35 kV MOA when it operates in linear region.