Reliability of directly-molded polymer surge arresters: Degradation by immersion test versus electrical performance

This technical report describes an experimental analysis of metal-oxide surge arresters applied to power distribution network. This analysis is performed from periodical measurements of leakage current of the samples and hydrophobicity of the external polymeric housing correlated to the aging/degradation process by saline water immersion at 90 °C for 3 months, in order to simulate 20 years of field application. Based on this evaluation, the useful life and time degradation of polymer arresters are analyzed from the progressive variation of their electrical characteristics as a function of the immersion time.