WATER TREES INFLUENCE ON THE POWER CABLES INSULATION BREAKDOWN DURING OPERATION

In this paper a study regarding the influence of water trees on the values and repartition of the electric field in power cables insulations is presented. Experiments were carried out on flat samples under the circular crown shape, taken from some high voltage cables insulations. In these samples water trees were developed and thermal parameters, water content from treed areas, dimensions and water trees density were measured. Using the dimensions of water trees, water content in treed areas and thermal properties, the electric field computation was done. The results show that the electric field values are strongly modified due to the development of water trees.