Electrode Extension Layer Design of DC Wall Bushing Based on Field Grading Material

Compared with traditional capacitor wall bushings, DC wall bushings based on field grading materials have several advantages, especially for high-voltage power systems. The electrode extension layer, the most important component of such DC wall bushings, is used to improve the electric field distribution at the flange. In this paper, the design principles of this layer are studied to develop guidelines for the design of its structural and material parameters under different voltage levels. For a given design precision of the electric field distribution at the flange, the length of the electrode extension layer should be minimized to reduce the total length of wall bushings.