Resistive component extraction of leakage current in metal oxide surge arrester: A hybrid method

Leakage current based condition monitoring is the most widely used method to ascertain the ageing of on-site Metal Oxide Surge Arrester (MOSA). The extraction of resistive component of leakage current is necessary for the exact health diagnostic of arrester. In particular, the third harmonic component of resistive current is known to be directly correlated with the ageing of arrester. Although, some existing methods are still used to extract the resistive leakage current but their computational procedures and accuracies have some limitations. This paper is aimed to propose a newly developed technique, referred as hybrid method for the extraction of resistive leakage current without acquiring the grid's voltage. This method was developed on SIMULINK software and then validated experimentally on 120 kV rated MOSA manufactured by ABB. Results have shown that the proposed method is 3.2% more accurate than the modified shifted current method. It can be implemented to develop a highly precise condition monitoring module for online monitoring of MOSAs.