Methods to Separate Resistive Leakage Current of ZnO Surge Arrester

In recent years the heavy transmission of power leads to destruction of surge arrester because of leakage current. This is the main problem that is being faced in power transmission sectors. Over voltages in power system may occur due to lightning, fault or switching operation. These over voltages could reach dangerous amplitudes for power system apparatus. Due to continuous passing the leakage current through the arrester they get weakened and rigorously blast. This can be dangerous for other equipments places at the substation like transformer and switches. To overcome this problem monitoring of surge arrester is important. Arresters are made up of the Zink oxide (metal oxide). We discuss various methods for measurement of leakage current through the arresters, simple but accurate method to separating the resistive leakage current from the total leakage current. In this method did not require the voltage measurement. The method based on the cancellation of capacitive leakage current from the total leakage current. A new method introduced which is based on harmonic analysis of leakage current.