Introduction
A thorough understanding of problems such as dry bands and electric discharges can only be achieved through accurate determination of electric field distribution along the insulator surface undera range of atmospheric conditions.Simulationsof the electric field over the surface of the insulatorsare intended to determine the high stress regions on the surfaceof the insulator. A commercial finite element package is employed for insulator modelling to determinetheelectric potential andtheelectric field distribution along the creepage distance of the insulator. In this chapter, computer simulation based on the Finite Element Method [FEM] is used to computethepotential andtheelectric field distributions along the creepage distance of theinsulators. Theinsulator model is developed forcoated and uncoated insulators under dry-clean and wet-polluted conditions with linearand non-linear pollution model characterised by field-dependent conductivity to achieve a better and more realistic field simulation. The conductivity of the pollution layer was assigned with a value based on laboratory measurements. It should be emphasised that, under normal conditions, polymeric surfaces would rarely be subjected to a uniform wetted surface situation, due to their excellent hydrophobic surface properties when new or undegraded. Nevertheless, the following simulation results help to identify the high field region that is vulnerable to dry band formations. The study discusses the modelling procedures and simulation results rather than the mathematics of the modelling process as these are considered more beneficial. However, the mathematics of modelling