Investigation results on semiconducting glaze and polymer insulators removed from a heavy contamination condition in China

This paper describes the investigation results of semiconducting glaze porcelain and silicone rubber polymer insulators removed from the transmission line under a heavy contaminated condition, the suburbs of Tianjin in China for 5 years in order to evaluate the long-term reliability of these insulators. Specimen insulator units were removed from the transmission lines periodically and some electrical and mechanical evaluations were carried out. From the evaluation results, no harmful deterioration on the removed semiconducting glaze and polymer insulator surfaces was observed.