Application of electric field calculations in optimisation of insulator designs

Abstract

When an insulator is placed in an electrode gap, its surface charge field distorts the geometric field, leading to a flashover at a voltage value dependent on the degree of the gap field distortion. This paper reports on studies conducted to determine the relationship between flashover voltages and electric field distribution along solid insulator surfaces. The surface electric field distribution along different insulator profiles was determined using the Finite-Difference method, and the flashover of the actual profile model measured. The obtained results show that each profile had a peak surface electric field and the higher the peak value, the lower the flashover voltage. The correlation curve for peak electric field and flashover voltage was developed using a curve fitting technique based on the Nelder-Mead simplex algorithm