三种绝缘子性能及其在特高压线路应用研究

对三种绝缘子的预期寿命、失效检出率、机械强度、尺寸重量、电击穿强度、电压分布、耐电弧性能、掉串事故、耐污性能应用场合和经济性分别进行比较。结合日本和俄罗斯特高压线路绝缘子选型经验,比较了我国±800kV直流特高压线路和1000kV交流特高压线路绝缘子选型区别,得出主要结论:在我国特高压线路上,Ⅱ级及以上污秽地区可考虑采用复合绝缘子;0和Ⅰ级污秽地区可考虑采用玻璃绝缘子;特高压直流输电线路上应考虑采用复合绝缘子。对于复合绝缘子在特高压线路应用中存在的问题,可以在导线侧挂若干个玻璃防污绝缘子来改善芯棒脆断;合理设计复合绝缘子的均压环来改善电压分布不均匀;采用合理的招弧设计来改善雷击闪络性能;采用2只组合结构来改善工频大电弧性能。

Characteristics of Three Kinds of Insulators and Their Applications Evaluation at Them in UHV Transmission Lines

Comparison between three basic insulator types(composite,porcelain and glass insulator)was made in respects of their service life,detected failure rate,mechanical strength,size weight electric breakdown voltage,voltage distribution,are resistance capability,string breaking rate,anti-pollution performance,occasion of application and economic estimation.Taking the insulator selection practice of Japan and Russia into referential consideration,the differences in selection of insulator type for ±800 kV UHV d.c.and 1 000 kV UHV a.c.transmission lines in China were compared,from which following conclusion were obtained: on UHV transmission lines composite insulators can be on pollution areas of classⅡ and above,glass insulators can be used in pollution areas of class 0 and Ⅰ,and composite insulators for UHV d.c.line.As regard to problems concerning UHV application of composite insulators,a few anti-pollution cap and pin type glass insulator string unite can be introduced in series at conductor end for preventing brittle fracture of FRP core.The grading ring of composite insulator shall be properly designed for improving non-uniformity of electrical distribution,reasonable arcing device shall be introduced for improving lightning flashover performance,and double string arrangement shall be used for enhancing power frequency large current resistance capability.