Out of the various techniques FDM is the simplest to compute and understand but the computation effort and computer memory requirements are the highest. Also, since all difference equations are ap- proximation to the actual field conditions, the final solution may have considerable error. Finite element method is a general method and has been used for almost all fields of engineer- ing. The method is suitable for estimating fields at highly curved and thin electrode surfaces with different dielectric materials. However, this method is more useful for uniform or weakly non-uniform fields and which can be represented by two-dimensional geometries. This method is recommended for three-dimensional complicated field configurations. Charge Simulation Method (CSM) is considered to be one of the most superior and acceptable method for two and three-dimensional configuration with more than one dielectric and with electrode systems of any desired shape since this method is based on minimization of the energy function which could be subjected to any operating constraints eg environmental condition, it has proved to be highly accurate method. Because of inherent features of the technique, this method also helps in optimising electrode configuration. In this electrode configuration optimisation problems the objective is to have feld intensity as low as possible subject to the condition that a constant field intensity exists on the complete electrode surface. With this optimisation, a higher life expectancy of high voltage equipments can be achieved.