ELECTROSTATIC STRESS ANALYSIS OF HIGH VOLTAGE CABLES

Khanjan N. Jariwala

Abstract: Power cable as one of the main components of power networks, play an important role in electric power transmission between different zones. In cable, stress will maximum nearer to the surface of the conductor and it will get decreases as we move away from core to outer sheath. So, dielectric will be unnecessarily strong and expensive. Moreover, in cable insulation system, due to presence of pollutant such as air voids, water voids and also occurrence of water treeing phenomena, local field increases. As a result, enhancing electric field may cause to local breakdown in cable insulation. The presence of water within the insulation material can only lead to forming water trees if a sufficient electric field exists which may shorten life of cable. In this thesis, Finite element method is used to computing and evaluating of the electric field in the power cable by considering to existence of water particle and air void inside the polyethylene insulation. For equal stress distribution, grading methods are also considered. For all this purpose FEMM software is used for modeling. The results indicate that the stress is influenced by the void permittivity, shape of void, sharpness of void and also void position. By providing grading of the cable we can equally distribute the stress along the cable insulation

Keywords: Cable grading, FEMM, Finite element method, cavity

DOI: https://doi.org/10.15623/ijret.2014.0304017