ONLINE MONITORING SYSTEM OF ZNO SURGE ARRESTERS BASED ON THE MEASURED LEAKAGE CURRENT

Zinc oxide arresters devices are essential in power system protection, contributing to increase reliability and to preserve the continuity of service and electric supply. These devices are installed between phase and ground transmission lines, with a small leakage current at Maximum Continuous Operating Voltage (low current region), and reaching high amplitude currents once a discharge takes place at high current region. At low current region, the leakage current consists of a capacitive and resistive component. Most leakage current monitoring systems of ZnO surge arrester are based on the measurement of the resistive component, because it can inform the degree of degradation of the surge arresters. However, it represents only about 5% to 20% of the total current. The study is focused on…