Finite element analysis of electric field distribution in XLPE cable insulation with presence of water trees and space charge

The presence of space charge changes locally the electric field distribution in power cable insulation and play an important role in tree development, thus accelerating the dielectric breakdown. This paper is concerned with the computation of the electric field in polyethylene-insulated power cables affected by water trees which grow from the inner and outer semiconducting layers, taking into account the space charge. Average charge values given by space charge measurements of an experimental paper were used for the electric field computation in cable insulation with continuous or/and individual water trees. Different parameters such as polarity of space charge, magnitude of space charge and water trees length variations considered and the effect of each have been well introduced. This paper shows that the space charge changes the electric field distribution inside and outside the trees (the field increases in some areas and decreases in others.) The obtained results show that, in the presence of water trees and space charge, the initiation of electric trees is more probable in the case of individual water trees than in the case of continuous water trees.

کلیدواژه ها:

electric field ، water treeing ، space charge ، cable insulation