Application of Finite Element Method to Three-dimensional Electric Field Computer-aided Simulation of UHV Wall Bushing

The ±800kV UHVDC wall-piercing bushing is the important equipment in ±800kV UHVDC transmission project in China. It is urgent to simulate and analyze the three- dimensional E-field of its key parts by using the finite element numerical calculation technology to determine the rationality of the traditional structure design and provide an optimization scheme. The actual working environment and rated operating parameters of wall bushing in converter station are analyzed. The three-dimensional electric field distribution of two kinds of the underpass wall bushing structures is simulated by finite element method. The electric field distribution characteristics of the metal shielding surface and its related accessories are analyzed. Three-dimensional solid model electric field analysis of middle connection structure of the bushing and the actual size of the supporting insulator is further carried out, and the structural type and size of supporting insulator are optimized. The results show under epoxy impregnated paper capacitive core structure, potential and electric field distribution along surface of the composite insulator through the wall and sleeve are relatively uniform, and the compact structure design of the sleeve can be realized. For the metal shielded core structure, the high field strength area is concentrated on the surface of metal shield and the external corona equalizing ring. Based on simulation results, ±660kV shrinkage wall-piercing sleeve has been developed and feasibility of ±800kV wall-piercing sleeve has been proved by all types of tests. The research results in this paper provide theoretical basis for design, development and operation of UHV wall bushing.