145 kV母线快速接地开关的结构设计与优化改进

Structure Design and Optimization Improvement of 145 kV Bus Fast Earthing Switch

145 kV GIS母线快速接地开关的结构是将快速接地开关静侧导体复合在母线导体上,快速接地开关动侧装配在母线壳体侧法兰上。在绝缘试验时发生几次放电,对该处结构进行分析,发现快速接地开关边相静侧屏蔽罩与壳体的距离较短,使得边相屏蔽罩上电场强度增大。同时,母线壳体焊缝恰好在快速接地开关断口处,焊缝的凸起和不均匀引起边相屏蔽罩电场分布不均匀,使该结构绝缘裕度持续下降。对该结构进行电场强度计算,计算结果表明,最大电场在快速接地开关边相静侧屏蔽罩处,印证了分析的正确性。根据分析结果,对快速接地开关静侧屏蔽罩进行结构改进,优化焊缝位置,优化改进后的结构电场强度小于许用值,并通过了绝缘试验验证,表明优化后结构的合理性。处理问题的方法及优化方向为类似结构的设计提供了方向和依据。

The structure of 145 kV GIS bus fast earthing switch is composed of the static side conductor of the fast earthing switch on the bus conductor,and the dynamic side of the fast earthing switch is assembled on the flange of the bus shell side.By analyzing the structure,it is found that the distance between the shield and the shell is smaller,so the electric field strength on the shield increases.At the same time,the welding seam of the bus shell is just at the fracture of the fast grounding switch,and the non-uniformity of the welding seam causes the non-uniformity of the electric field distribution of the side-phase shield,which aggravates the decrease of the insulation margin of the structure.The electric field strength of the structure is calculated.The results show that the maximum electric field is at the shield of the static side of the phase of the fast grounding switch.According to the analysis results,the structure of the static shielding cover of the fast grounding switch is improved,the position of the welding seam is optimized,and the electric field strength of the improved structure is less than the allowable value,which is verified by the insulation test,it shows the rationality of the optimized structure.The method of solving the problem and the direction of optimization provide direction and basis for the design of similar structures.