Simulation and Optimization of Electrostatic Field in 40.5kV Inflatable Switchgear Cabinet

The current rapid development of China's power transmission and transformation industry, inflatable switchgear has excellent environmental adaptability and small size, in the transmission and distribution network has been widely used. In order to further enhance the application range of inflatable cabinets, it is important to optimize the insulation performance of miniaturized switchgear. In this paper, electrostatic field simulation of 40.5kV inflatable switchgear based on the finite element method is carried out to judge the internal electric field distribution. Simulate and analyze the potential distribution and electric field strength distribution under the operating condition of the circuit breaker of the inflatable switchgear. The simulation results show that the electric field of sulfur hexafluoride in the outer shell of the inflatable switchgear is more concentrated near the poles, and the maximum value of the electric field reaches 78.2kV/mm, which exceeds the breakdown strength of the sulfur hexafluoride medium by 9kV/mm. Subsequently, the problem of excessive localized field strength is solved by studying the effects of conditions such as the length of the metal shielding ring and the radius of the metal crimp on the shielding effect. According to the simulation data, maintaining the volume and basic layout of the existing inflatable switchgear cabinet unchanged, after adding the optimized grounded metal shielding ring, the field strength at the pole and shell can be reduced to less than 9kV/mm, which meets the insulation requirements. The research results of this paper can provide theoretical guidance for the optimal design of the insulation of inflatable switchgear.