输电线顺线路方向风荷载及分配模式

Along-line wind loads and distribution patterns of transmission lines

采用风洞试验,结合有限元分析方法,研究输电线顺线路方向的风荷载和作用模式;研发弧形输电线风荷载的风洞试验测试装置;获得2种典型垂跨比输电线的顺线路方向比例系数;通过2个实例对比输电线顺线路方向风荷载的3种分配模式,给出输电线顺线路方向风荷载和分配模式的建议.研究表明,各国规范中只有中国规范给出了顺线路方向风荷载的规定;垂跨比为4%和8%的输电线顺线向荷载比例系数均低于0.15,中国规范取值(0.25)偏保守;按投影高度和按规范中拉索体型系数的分配结果基本一致;按弧长分配会比按其他2种方法获得更大的竖向位移和水平位移,增大幅度约为12%;顺线路方向的比例系数建议取0.10(常规输电线)或0.12(大跨越输电线);顺线路方向的风荷载建议采用按投影高度进行分配.

Wind tunnel tests and finite element analysis methods were employed to obtain along-line wind loads and distribution patterns of transmission lines.The testing facilities were developed to measure the wind forces of curved transmission lines in a wind tunnel.Along-line wind load proportional coefficients of transmission lines with two typical rise-span ratios were obtained.Three distribution patterns of along-line wind loads of transmission lines were compared through two cases.Finally,suggestions for along-line wind load and distribution patterns of transmission lines were given.Results show that only the Chinese codes specify the wind loads of transmission line in the alongline direction.The along-line wind load proportional coefficients of two transmission lines with rise-span ratios of 4%and 8%are both less than 0.15,and a recommended value of 0.25 in the Chinese codes is conservative.The distribution patterns based on projection heights and body shape coefficients of cables regulated in the Chinese code are almost the same.The distribution pattern based on arc lengths results in larger vertical and horizontal displacements compared with the other two patterns,with an increasing value of about 12%.The along-line wind load proportional coefficient is suggested to be 0.10 for regular or 0.12 for long-span transmission lines.And the distribution pattern of along-line wind loads is suggested to be distributed by projection heights.