Metal oxide arresters are widely used in power systems of various voltage levels. They are prone to moisture or aging due to long-term use of power frequency voltages, resulting in excessive leakage current, which seriously affects the safe and stable operation of power grid equipment. In this paper, through routine tests on metal oxide arresters, it is found that the DC leakage current at 75% U1mA exceeds the standard, and it is judged that the valve may be aging or the possibility of porcelain cracks. Then, the disassembly inspection of the problem arrester can find out the cause of the arrester failure and verify it. Preliminary test results can better guide the manufacture and operation and maintenance of arresters

lightning arrester；Leakage current；Reference voltage；disintegration