Unlike surge arresters in substations, obtaining voltage vector information for surge arresters installed on lines is difficult. Therefore, this paper presented a voltage-signal-independent resistive leakage current extraction algorithm for surge arresters and developed an online monitoring system. In this paper, the leakage current characteristics of surge arresters are firstly simulated and analyzed. Then, the resistive leakage current extraction algorithm that is voltage-signal-independent is proposed. In addition, the algorithm proposed in this paper reduces the impact of the third harmonic of the power system on the measurement accuracy greatly. Finally, the online monitoring system for resistive leakage current of surge arrester developed in this paper has been verified by simulation and experiment, which proves the effectiveness of the system. And it is available to break out of difficult situations where it is hard to measure data of resistive leakage accurately, and also improve the efficiency of the operation and maintenance staff.

Surge arresters; online monitoring system; leakage current; resistive leakage current.