Compact Design for 550 kV GIS Insulation System

Abstract

To reduce the usage of SF6gas, downsize equipment's volume, and enhance basin-type spacers' electrical and mechanical performance in gas insulated metal enclosed switchgear (GIS), compact design of spacer based on finite element method is conducted. In the context of reducing 15% insulation distance, electrical and mechanical properties can be improved by optimizing spacer's structure and dielectric properties distribution concurrently. Local concentrated mechanical stress and deformation amount under the pressure of 2.4 MPa are relieved. Besides, surface electric field is well-distributed by adjusting spacer's profiles, thickness at two terminals, and permittivity distribution at the region nearby the flange, resulting in ideal reverse “U” shape distribution. Comparing with original insulation system, structure after compact design shows approximately 20% decrease of SF6 usage amount and 11.9% reduction of epoxy composite weight. Moreover, the maximum electric field intensity along the convex or concave, and the maximum deformation of spacer could decrease by 17.0%, 21.2%, and 29.9%, respectively. This design strategy for GIS insulation system takes both electrical and mechanical properties into account, and exhibits significant improvement of comprehensive performance of spacer.