±800 kV特高压直流大跨越悬垂绝缘子串均压方案优化

Optimization of Grading Rings Design for ± 800 kV HVDC Large Crossing Transmission Line Suspension Insulator String

绝缘子串表面的场强和电位分布存在明显的不均匀性,目前国内外进行的相关研究多集中在超高压及特高压交流领域,对直流线路的相关研究较少。加之直流线路大跨越工程并不常见,国内外对直流线路大跨越超长复杂绝缘子串电场及电位分布的系统研究较为缺乏。在现有最新研究成果的基础上,建立三维有限元模型,系统分析均压环的参数变化对均压效果的影响,综合考虑均压环参数对沿绝缘子串表面的场强、整串绝缘性能及工程造价的影响,初步选定均压环的优化方案,最后采用多变量有约束的最优化理论,选定最优的均压方案。研究结果表明,优化后单片绝缘子承受的最大电压降低约5. 7%。

The distribution of electric field and potential along the insulator string is obvious uneven. At present,the domestic and foreign researches mainly focus on the EHV and UHV AC line. However,the HVDC large crossing transmission line is not very common,so there is a lack of systematic research on the electric field and potential distribution of large crossing and complex insulator strings. Based on the latest research results,this paper establishes three-dimensional finite element model and research the influence of grading ring parameters,considering the influence of insulator surface field strength,the insulation performance and the cost of the project construction,this paper preliminary select optimization scheme of grading ring. Finally,the optimal scheme is selected by using the theory of multivariable constrained optimization. The results show that the maximum voltage of the single insulator is reduced by about 5. 7% after optimization.