Electric Field Simulation and Structure Optimization of 12 kV Environmental-Friendly Gas Insulated Ring Network Cabinet

The environmental-friendly gas-insulated ring network cabinet is referred to as an environment-friendly cabinet. The high-voltage circuit parts of the environment-friendly cabinet are mainly composed of conductors, VCB, and the knife-brake type three-station disconnector. The insulating support parts are composed of insulating board, insulating arms, and so on. The grounding parts consist of a metal shell and grounding contacts. Simulation of the electrostatic field of the environment-friendly cabinet is during the condition of isolation fracture. Simulation results show that there are local high electric fields on the metal surfaces of the support for VCB, moving contacts, and static contacts, which are 20.7SkV /mm, 10.06kV/mm, and 7.41kV/mm, respectively. Adding a thin metal sheet to the support for the VCB or filling the gap with silicone rubber will reduce the electric field to 4.S1kV/mm and 4.1kV/mm, respectively. The metal shielding structures are installed on both sides of the moving contact and the static contact of the disconnector, and the surface electric field intensity is reduced to 5.25kV/mm and 5.18kV/mm respectively on the disconnector during the state of isolation fracture. The optimized environment-friendly cabinet was tested for power-frequency voltage-withstand test and partial discharge. The results showed that the optimized environment-friendly cabinet passed the power-frequency voltage-withstand test and the magnitude of partial discharge was better than the initial scheme, which verified the feasibility of the optimization.