Optimization on the internal insulation system of gas‐insulated bushing for 1100‐kV GIS based on multiobjective optimization method

Abstract

AbstractIn this paper, we first study the voltage and electric field distribution characteristics under the basic lightning impulse level (BIL) of 2400 kV by finite element method (FEM) calculation which are affected by the internal shielding structure of the gas‐insulated bushing for the 1100‐kV gas‐insulated substation (GIS). On this basis, four parameters of the shielding structure are determined to be the decision variables in the optimization process. Four electric field objective functions and four potential objective functions are also proposed. Using a multiobjective optimization method, we then construct an evaluation function with the eight objective functions mentioned above, which are used to evaluate the electric field and potential distribution synthetically. Furthermore, a combination of FEM and the evolution strategy is used to construct the stochastic optimization objective function with the multiobjective evaluation function. The electric field and potential distribution of the gas‐insulated bushing are greatly improved after optimization, and the electric field strength at key spots is effectively reduced. The insulation system of gas‐insulated bushing for 1100‐kV GIS designed by this method has passed type tests and worked well nearly 3 years. So, this optimization provides a constructive method and useful basis for the design of gas‐insulated bushings for 1100‐kV GIS and other electrical equipment. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.