温度分布及绝缘表面凝露对SF6绝缘柱上真空断路器内部电场的影响OA

Pole-mounted switch is a critical equipment in distribution network,and its stable operation is essential to the safety of power grid.In recent years,the pole-mounted witch has experienced frequent failures.Post-failure disassembly analysis shows that moisture ingress caused by aging failure of equipment seal is the direct contributign factor.Given that moisture ingress is closely correlated with the internal temperature distribution and electric field distortion within the equipment,it ultimately leads to insulation degradation and failure.To this end,in this paper type ZW20-12/630 A vacuum circuti breaker is taken as an example to study and simulate the distortion of the inter-nal electric field caued by temperature and surface condensation on the insulation.First,a two-dimensional simula-tion model is established based on the CAD drawings of the pole-mounted switch.The finite element software Ansys maxwell is used to simulate and calculate the dielectric and conductor losses inside the normal equipment.Then,the internal temperature filed distribution of the pole-mounted switch is calculated through fluent software,the oba-tined temperature field data is imported into the electric filed calculation module,where the dielectric constant of the material is corrected in accordance with the temperature distribution,thereby obtaining the electric field distri-bution taking into account the temperature.The condensation model is added to the moisture-prone parts of the pole-mounted switch to study the influence of three moisture conditions on the electric field distribution.The results show that both internal temperature distribution and surface condensation cause varying degree of electric fieldd dis-tortion inside the equipment.The electric field distrotion in certain area such as incoming bushing area even ex-ceeds the dielectric strength of the gas insulated medium,which can readily trigger partial discharge and subse-quently lead to insulation failure.The research results in this paper lay a theoretical foundation for explaining the mechanism of insulation failure caused by moisture on the pole-mounted switch and developing the corresponding detection methods.