Influence of power system´s harmonic voltage and interphase interference to resistive leakage current of MOA

Surge arrester is an important over voltage protection equipment in substation, and the latent faults of MOA can be found by on-line resistive leakage current monitoring. However, the existence of harmonic voltages in the power system will influence the monitoring accuracy. At the same time, because of influence of location and distributing mode of MOA, the voltage of two other phases affect single MOA by interphase interference, and this will surely influence the monitoring accuracy of MOA´s resistive leakage current too. In this paper, these influence is analyzed and an improved compensation method to separate the resistive leakage current under the existence of harmonic voltage is described. And the methods to eliminate interphase influence is analyzed.