Study on the partial discharge characteristics of the XLPE insulation samples during electrical treeing ageing

The partial discharge characteristics in the XLPE insulation during electrical treeing ageing are studied in this paper. The condition of electrical tree initiation is well established under ac stress. Specimens using point-plane electrode geometries in XLPE insulated samples have been investigated. Using the partial discharge detection system, which includes traditional detecting method and ultra-wideband (UWB) partial discharge detecting method, the partial discharge characteristics of XLPE insulation during treeing are studied. We can find that the characteristics of UWB partial discharge signals have a change observably in the time-domain and frequency-domain during electrical treeing. The high energy density area of the partial discharge signals of the XLPE insulation specimens moves to the higher frequency during electrical treeing. Thus, the status of XLPE insulation can be evaluated by detecting the partial discharge signals occurring in them. It is important of this research for evaluating the status of XLPE power cables in service.