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Metal oxide surge arresters are important equipments that apply to power system for protection against switching and lightning over-voltages. Surge arrester monitoring technique based on leakage current analysis is a conventional monitoring method. Lack of proper features and thresholds is most important limitation of this method. In this paper, new monitoring indexes for surge arrester diagnostic are proposed to determine surge arrester condition under different situations including clean condition, surface contamination and ultraviolet aging. The experimental tests have been performed on polymer surge arresters to evaluate the ability of the proposed indexes for distinguishing the operating condition of surge arresters. Results have been shown the viability of the new indexes on surge arrester monitoring procedures. The investigation and the discussion of the produced results can give good ideas the electric engineers in order to easily analyze arresters’ condition leading to effective schedule maintenance. [ABSTRACT FROM AUTHOR]

This paper presents proper indicators for evaluation of the surge arrester condition based on the leakage current analysis. Maximum amplitude of fundamental harmonic of the resistive leakage current ( I mr1 ), maximum amplitude of third harmonic of the resistive leakage current ( I mr3 ) and maximum amplitude of fundamental harmonic of the capacitive leakage current have been used as indicators for surge arrester condition monitoring. The effects of operating voltage fluctuation, third order of voltage harmonic, over-voltage and varistor aging have been investigated to show the ability of introduced indicators for accurate diagnostic of arrester’s conditions. In order to have accurate values of stray capacitors, 3D-FEM has been used. Moreover, surge arrester model for calculating leakage current has been performed in ATP–EMTP. In addition, the signal processing has been done using MATLAB software. This study shows that the introduced indicators are proper criteria for surge arrester condition monitoring. [ABSTRACT FROM AUTHOR]