前苏联1150kV交流输电线路绝缘子串的选择

介绍了前苏联选择1150kV交流特高压输电线路绝缘子串的基本原则:①必须综合考虑污秽等级、爬距的有效利用、串长、多串组合时击穿强度的变化、绝缘子形状和长期最高运行电压等一系列因素后,再确定绝缘子的几何爬距;②在特高压电网的规划设计阶段,可先根据现场污秽情况、较低电压等级线路的多年运行经验、沿规划线路布置的测试点的试验数据等,利用正态分布的办法估算线路在最大长期运行电压下的年闪络率,然后决定绝缘水平;③在难以得到实际年闪络率的情况下,可用每百公里线路绝缘子的允许年闪络率来确定绝缘水平,从而确定有效爬距,再根据质量指标(闪络梯度)来选择绝缘子的物理结构。文章还分析了绝缘子多串并联和长度变化对击穿电压的影响,指出瓷长棒绝缘子由于年故障率很低,具有广阔的应用前景。

An Introduction to Selection of 1150kV Line Insulation Strings in Russia

The author introduces the basic principle of selecting the insulator strings for 1150kV ultra-high voltage transmission line in Russia. The geometrical creepage distance of insulator should be determined after comprehensively considering a series of factors, such as the pollution level, the efficient use of creepage distance and the string length, the breakdown strength of multiple-string insulating structures, the insulator shape, and maximum operating voltage. At the planning and design stage of ultra-high voltage transmission line, the annual number of flashovers per 100km of transmission line should be estimated based on local pollution severity, operational experience of lower voltage lines, and test data along test stations by the integral function of normal distribution and then the insulation level is decided. When actual flashover rate is not available, it is appropriate to enter this parameter with the needed rate to get insulation level and creepage. The impact of the parallel number and length of string on breakdown strength of insulator are also analyzed. It is also pointed that the porcelain long-rod insulator with the much low annual failure rate, holds a better application prospects. The obtained results should be helpful in selecting insulator of the first UHV line in China.