Leakage current refers to the current flowing through the arrester valve core after the arrester is connected to the system. Because lightning arresters are usually similar to insulators, this current is quite small without overvoltage. About no more than 1MA. If it becomes larger, it shows that the performance of the valve plate in the arrester core has decreased. The online monitor has an ammeter with green, yellow and red ranges. The pointer in the green range indicates good performance, the yellow range indicates that the leakage current is slightly larger, and the red range indicates that the lightning arrester needs to be replaced. Because lightning arresters are fully enclosed and integrated equipment, they generally do not need maintenance.

The leakage current (full current) of a complete MOA can be divided into three parts: capacitive current generated by zinc oxide valve plate (column), nonlinear resistive current generated by zinc oxide valve plate (column) and current generated by lightning arrester insulation structure.

If the leakage current generated by the insulation structure increases, the peak value of the total current will also increase. In rainy days, the pollution is serious and the water flow is generally too large. Of course, due to the structure, the current will be very small.

In addition, due to the increase of leakage current caused by the valve plate inside the arrester, the arrester needs to be tested and "retired" On-line monitoring of green zone, yellow zone and red zone has certain early warning function, but in the use experience, it is not in the green zone, and the red zone with good performance indicates that the arrester needs to be replaced.