高海拔地区特高压直流复合支柱绝缘子伞裙优化和污闪特性研究

发布时间：2018-06-18 11:46

本文选题：复合支柱绝缘子 + 高海拔　；参考：《华南理工大学》2014年博士论文

【摘要】：为有效改善复合支柱绝缘子的直流污闪特性，增加换流站外绝缘裕度，本文首次在高海拔地区系统地开展了复合支柱绝缘子伞裙参数优化研究，并全面开展了伞裙参数优化后的大尺寸复合支柱绝缘子（5支复合支柱绝缘子串联）直流污闪特性的研究。主要内容如下： 1）基于电磁场理论，利用ANSYS软件采用有限元法建立一大一小伞形和一大两小伞形的大尺寸染污复合支柱绝缘子仿真模型（5支复合支柱绝缘子串联），对不同伞裙参数的复合支柱绝缘子的沿面电场分布特性进行仿真研究，通过对比分析沿面平均电场强度和沿面电场不均匀系数，揭示了复合支柱绝缘子伞伸出、伞间距对沿面电场分布的影响规律，给出了相对应的参数优化范围，为后续伞裙优化试验所需的复合支柱绝缘子试品提供了伞裙参数范围。 2）以仿真研究推荐的试品参数范围为基础，选取各类具有代表性不同伞裙参数的支柱绝缘子试品，在昆明国家特高压工程实验室进行历时9个月的自然积污试验，所有试验试品均在相同自然环境中放置9个月，通过对比各类试品表面自然积污量的大小，揭示了不同伞裙参数、不同材质和带电状态等因素对支柱绝缘子自然积污特性的影响规律，为复合支柱绝缘子的选型和设计提供了优选方案。 3）对50余支不同伞裙参数的复合支柱绝缘子试品进行了人工污秽试验，系统地研究了伞裙参数对直流污闪电压的影响规律，给出了最优的伞裙参数值，推荐了大伞伸出和大伞间距的最佳配比值及取值范围；基于最小均方差法，拟合构建了伞伸出、伞间距与直流污闪电压的二次函数关系，并从沿面电阻、紫外放电特性、沿面电弧发展特性和爬电距离利用率方面探讨了伞裙参数对复合支柱绝缘子直流污闪电压的影响机理。 4）研究了优化后的大尺寸复合支柱绝缘子（5支复合支柱绝缘子串联）的直流污闪特性，获得了两类不同伞形结构下大尺寸复合支柱绝缘子直流耐受电压曲线和污秽因素（盐密、灰密和污秽不均匀分布）对直流污闪电压的影响规律，对比了大尺寸试品和短串试品的直流耐受电压曲线，验证了直流污闪电压与复合支柱绝缘子串长的线性关系；通过对试品沿面电阻、紫外放电特性和沿面电弧发展特性的研究，探讨了污秽因素影响直流污闪特性的本质，分析了造成大尺寸试品与短串试品直流污闪特性差异的原因。 5）通过分析换流站自然污秽量的污秽成分，并对其污秽测量值进行修正，，确定了换流站外绝缘污秽水平，然后基于伞裙优化研究结果，直接采用优化后的大尺寸复合支柱绝缘子试品（5支复合支柱绝缘子串联）的试验数据，运用污耐压法对±800kV楚雄特高压直流换流站的复合支柱绝缘子串长进行了优化设计，并对即将建设的±500kV富宁、永仁超高压直流换流站复合支柱绝缘子的外绝缘尺寸进行了设计。
[Abstract]:In order to improve the DC flashover performance of composite strut insulator effectively and increase the outer insulation margin of converter station , the research on parameter optimization of composite strut insulator umbrella skirt was carried out in high altitude area for the first time .

1 ) Based on the theory of electromagnetic field , the finite element method was used to establish a large and small umbrella - shaped large - sized composite strut insulator simulation model ( 5 composite strut insulators series ) , and the distribution characteristics of the composite strut insulators with different umbrella skirt parameters were simulated .

2 ) Based on the range of test article parameters recommended by simulation research , all kinds of pillar insulator test article with representative different umbrella skirt parameters were selected . All the test articles were placed in the same natural environment for 9 months . All the test articles were placed in the same natural environment for 9 months , and the influence law of different umbrella skirt parameters , different materials and charged states on the natural contamination characteristics of the pillar insulators was revealed by comparing the size of the natural product contamination on the surface of various test articles . The selection and design of the composite column insulators provided the preferred scheme .

3 ) The influence of the parameters of the umbrella skirt on the DC flashover voltage is studied systematically , and the optimal value of the umbrella skirt parameter is given , and the optimum ratio and the range of the value of the big umbrella extension and the large umbrella spacing are recommended .
Based on the minimum mean square error method , the quadratic function relation of the umbrella extension , the spacing of the umbrella and the DC flashover voltage is fitted , and the influence mechanism of the parameters of the umbrella skirt on the DC flashover voltage of the composite strut insulator is discussed from the aspect of the surface resistance , the ultraviolet discharge characteristic , the development characteristic of the surface arc and the utilization rate of creepage distance .

4 ) The DC flashover characteristics of the optimized large - sized composite strut insulators ( series of five composite strut insulators ) were studied . The effects of DC withstand voltage curves and contamination factors ( salt density , ash density , and dirty non - uniform distribution ) on DC flashover voltage were obtained . The linear relationship between DC flashover voltage and insulator string length was verified by comparing the DC withstand voltage curve of the large - sized test article and the short - string test article .
Based on the study of surface resistance , ultraviolet discharge characteristics and arc development characteristics of the test article , the essence of the influence of the pollution factors on the characteristics of DC flashover is discussed , and the reason of the difference between the direct current emission characteristics of the large - sized test article and the short - string test article is analyzed .

5 ) By analyzing the dirt content of the natural sewage of the converter station and correcting the dirty measurement value , the test data of the outer insulation pollution level of the converter station is determined , and then the optimization design of the composite strut insulator string of the 卤 800kV Chuxiong ultrahigh voltage DC converter station is directly adopted based on the result of the optimization of the umbrella skirt . The external insulation dimensions of the 卤 500kV FuNing and Yongren ultra - high voltage DC converter are designed .
【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM216

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