Capacitor bushing optimization via electrostatic finite element analysis

In high-voltage capacitor bushings, there is maximum field intensity at the edge of the aluminum foil and where foils overlap. Any technique decreasing much field intensity in those regions will significantly optimize the bushings’ electrostatic characteristics. This paper presents the study of the effect of edge diversion in the overlapped region of an aluminum foil and of the shape of aluminum foil edge in improving the maximum field intensity of the overlapped region. Electrostatic analysis was used to minimize the field intensity. 2D and 3D simulations and analyses were run, respectively via finite element method magnetic (FEMM) and Vector Field Opera. Techniques improving field intensity distribution of capacitor bushing are presented. Results show that foils that are not folded and have the inner edge placed lower than the outer edge better distribute the field around the edges. Key words: Capacitor bushing, cavities, electric field, electrostatic simulation, finite element analysis.