Evaluation of the varistors microstructure quality by measuring higher harmonics in the current

The purpose of the presented work was to find the relationship between the varistor's microstructure parameters and the current flowing through the surge arrester for different voltage levels. The tests were performed on a randomly selected population of non-spark surge arresters in polymeric shields intended for operation in medium voltage networks. The reference waveforms were measured for the tested population. Higher harmonics participation in the current wave was assumed as the evaluation criterion. The work is an introduction to a wider range of research carried out as part of joint activities of the laboratories of the Institute of Power Engineering and the Institute of Fundamental Technological Research PAN. (Evaluation of the varistor's microstructure quality by measuring higher harmonics in the current).