Research of the electrical trees growth and PD in HV XLPE cable

Online observing the growth of electrical trees in 10kV and 35kV XLPE cable section and monitoring its PD characteristics have been conducted. With operation phase voltages, the electrical trees were branch like trees. With same voltage, the time electrical trees grew in XLPE insulation was same, but the breakdown time of semi-conductive layer had big difference results and had large dispersion. When single tree reached semi-conductive layer, the cable was not breakdown and the voltage would last a period of time. As the growth of electrical trees, PD did not last all the time. There was weakened stage of PD in 10kV and 35kV XLPE cable. The peak of intensity of PD appeared before electrical tree reached semi-conductive layer.