500kV输电线路悬垂绝缘子串风偏闪络的研究

Study on Flashover of Suspension Insulator String Caused by Windage Yaw in 500kV Transmission Lines

近年来,500kV输电线路风偏闪络事故频繁发生,其频率已超过电力系统安全运行可接受的限度。按照标准设计的输电线路在实际运行中应该是安全的,但自从500kV输电线路第2代杆塔投入使用以来,风偏闪络事故的发生率逐年上升,这在理论上分析是不合理的。文章从500kV输电线路悬垂绝缘子串的风偏角计算模型入手,对风偏角计算所采用的静态受力平衡算法存在的问题进行了详细分析,给出了一种最大风偏角的修正方法;在确定杆塔与导线之间最小空气间隙时,传统做法是通过复杂的几何作图来估算,文中通过在杆塔计算模型中引入笛卡儿二维坐标系使计算更为简洁方便,且提高了准确度;最后对目前风偏现象研究中存在的几个主要问题进行了详细分析。

In recent years, windage yaw flashover frequently occurs in 500kV transmission lines, and the frequency of such accident exceeds the receivable limit of power system secure operation. The transmission lines designed according to standard are supposed to be secure in practical operation, however, since the second generation of transmission towers for 500kV transmission line are put into operation, the incidence of windage yaw flashover increases year by year, and it is unreasonable theoretically. Starting with the calculation model of windage yaw angle of suspension insulator string for 500kV transmission line, the existing problems in static stress balancing algorithm adopted in windage yaw angle calculation are analyzed in detail, and a modified method for maximum windage yaw angle calculation is given; to determine the least air clearance between tower and conductors, the traditional way estimates it by complex geometrical construction, in this paper by means of leading the two dimensional Descartes coordinate system into tower calculation model the calculation becomes more sententious and convenient, and the calculation accuracy is improved. Finally, detailed analysis on main problems existing in present research on windage yaw phenomenon is conducted.