Optimization of high voltage insulators within three dimensional field distributions

In previous articles a method was presented for optimizing high voltage insulators by means of cubic splines, which was restricted to the condition that both, the insulator and the field distribution should be axially symmetrical. In this paper the possibilities of optimizing high voltage insulators within three dimensional (not merely axially symmetrical) electrostatic field distributions are analyzed. As proposed previously, the minimization of total field strength intensity was chosen as the optimization criterion. The optimization is carried out by means of an iterative process. An axially symmetrical high voltage insulator is taken as a starting point During the process the shape of the surface is modified while preserving the axial symmetry of the whole piece. In each iteration the distribution of the total field strength intensity is calculated along a predefined set of generating curves of the axially symmetrical original contour. For each generating curve of the set a modified curve is calculated. From all the modified curves a new unique generating curve is determined. The shape of the new contour is obtained using smoothing cubic splines. The functionality of the proposed method is shown for two test arrangements with different degrees of asymmetry.