Study on Partial Discharge Characteristics During Electrical Tree Growth at XLPE-SIR Interface

Abstract

The cable attachment interface has always been a weak insulation link in cable systems. In this paper, the growth characteristics of electric tree at the interface was studied at 70 °C, and the growth morphology and partial discharge (PD) signals of electric trees were collected simultaneously. The cross-linked polyethylene (XLPE) and silicone rubber (SIR) were pressed together by a pressing device, and AC high pressure was applied to a steel needle that is vertically inserted 1mm from the XLPE-SIR interface, with a pin plate spacing of 2mm. It was shown that there was a growth pattern of "trigger-rapid growth-stagnation-breakdown" in the electric tree at the interface. It was found that the amplitude and frequency of partial discharge are closely related to the growth stage of electric tree. The relationship between the growth characteristics of electrical tree and the partial discharge signal at the interface was established, which provided the experimental basis for the online monitoring technology to judge the insulation state of cable accessories more accurately.