A Review on Leakage Current Sensing Technologies of Metal-oxide Arrester

Metal-oxide Arrester (MOA) is the most widely used arrester in power systems, which protects electrical equipment from high transient overvoltage by limiting continuous flow time and amplitude. Operation experience shows that condition diagnostic technique has played an essential role in the timely detection of MOA aging and its insulation damage risk. Leakage current, which is very weak and in an intense electromagnetic environment, is an essential index in MOA state diagnosis. Accurate sensing of leakage current has always been one of the difficulties in MOA online monitoring. Based on the analysis of the leakage current characteristics of MOA, this paper sorts out and compares various leakage current sensing methods, evaluates the factors affecting leakage current value, and discusses the further development of leakage current sensing technology with a FEM simulation.