THERMAL ANALYSIS OF HV CABLES UNDER DIFFERENT OPERATING CONDITIONS

Abstract

This thesis provides a comprehensive study on temperature distribution for both the underground cable components and its surrounding environment. The major factors affecting cable ampacity are studied such as soil thermal resistivity, cable depth and soil temperature. Further, various types of insulations such as XLPE, PVC, EPR, SF6 and Engine oil are subjected to the investigation at different configurations. The effect of the change of the frequency spectrum of the nonlinear load current is also extensively studied to estimate the required derating factor in the presence of harmonics. Finite element method is employed using COMSOL Multiphysics software to perform heat transfer analysis and obtain the steady state and the transient temperature by implementing the heat diffusion equation. It is thought that the developed model can be utilized for better thermal design of the power cables and for the real-time temperature prediction of that in service in the presence of harmonics for a cable system.