Electric Field and Potential Calculation in 10, 15 and 20 kV Water Infested Power Cables

Power cables are used in the transmission network in cities and for overseas power transmission. The polyethylene cables used for medium voltage were vulnerable to breakdown due to water treeing. Water treeing significantly reduces the electric breakdown strength of the insulation. The presence of water tree results in the reduction of their dielectric strength. Here the finite element simulation technique is used to evaluate the electric field inside the 10 kV 15 kV and 20 kV power cables. A model that illustrates the water-dielectric interface within the cable insulation system is proposed. The link between the local field concentration in the vicinity of water void and the possibility of insulation failure, which can be developed to a complete breakdown is discussed.