Analysis and Optimization of Electric Field Distribution in 1200kV SF6 Insulated Power Frequency Test Transformer

With the fast development of HV and EHV underground substations in large cities, the demand and technical challenge of field insulation test for HV and EHV power transmission equipment is increasing fast also. As the traditional field insulation test equipment, oil-immersed cascaded power frequency test transformer is very difficult to face the challenges because of its large size and weight. SF6 insulated test transformer, as the new site test equipment, also needs to be designed smaller in size. As a result of the size reduction, it will increase the risk of breakdown and partial discharge. This paper introduces the electric field analysis and design optimization of a newly designed 1200kV SF6 insulated test transformer. The finite element analysis software INFOLYTICA is adopted for the electric field simulation. The simulation results demonstrated its main design of size and insulation. In some particular regions where the electric field is significantly uneven distributed, optimization design is provided.