Partial discharge characteristics of XLPE cable joint and interfacial phenomena with artificial defects

This paper deals with partial discharge (PD) causing degradation of XLPE cable joint and interfacial phenomena of XLPE/EPR interface due to artificial defects such as metal particles, needle-like void and fiber soaked with water. We measured aging time dependence of phase-resolved PD (phi-q-n) patterns and PD statistic parameters when such kinds of defects were placed at XLPE/EPR interface. As a result, phi-q-n patterns were found to depend upon the defect type varying with aging time. In order to grasp the degradation mechanisms, we compared a practical XLPE cable joint with a model sample to simulate the real one. Moreover, electron spectroscopy for chemical analysis (ESCA) was also carried out to interpret the degradation mechanism.