ELECTRIC FIELD EFFECT IN THE FORMATION OF WATER TREEING

In this paper a MV (medium voltage) of 11 KV XLPE (cross linked polyethylene) power cable is implemented in COMSOL MULTIPHYSICS. This software simulates the results based on FEM (Finite Element Method) in order to know the stress effects of electric field in the formation of water trees. Water voids form when there is mechanical damage while laying directly or buried in ducts and water penetrates through the cable sheath. So the impurities fill the cable and result in treeing which develops slowly. The results show the field effect is more at the corners of the ellipse shaped water void which direct radial outwards from the cable axis. This maximum value of electric field causes the formation of channels between the micro cavities which further leads to breakdown