The experimental study on tree growth in XLPE using 3D PD patterns

In order to reveal the mechanism of electrical tree growth in insulation, a 29 kV CN-CV cable sample is studied. The experiment is based on research for determination of the dependencies between PD characteristics in XLPE upon time and three dimensional PD patterns of corresponding treeing. The investigations were carried out by means of electrical measurement of PD current and simultaneous optical recording of treeing images. The needle-plane electrode is applied as part of the test system. As a result, -q-n PD patterns from to bush tree initialization and growth can be obtained. Test results show that PD pattern recognition can be applied as a useful tool for recognizing electrical tree growth and monitoring the cable condition. This can make a good basis for on-line monitoring of power cables.