输电线路覆冰失效分析

在输电塔线体系的设计过程中,导线和铁塔结构是分开进行设计的.由于对铁塔的纵向不平衡张力缺乏有效的计算方法,通常是根据规程取导线最大使用张力的比例进行校核.然而,不平衡张力是危害输电线路安全稳定运行的重要因素之一,精确计算由档距、高差和不均匀荷载引起的纵向不平衡张力有着重要的意义.文中应用梁单元和索单元对输电铁塔和导线建立整体单元模型,对输电塔线体系结构覆冰荷载进行有限元计算,分析了均匀覆冰荷载下铁塔的极限承载力,对在实测不均匀覆冰荷载下的倒塔失效原因进行了分析,指出了输电线路中的薄弱点,对铁塔提出了提高冰厚等级改造的建议.

Failure analysis of iced power transmission line

During EHV transmission system towels and lines design, the structure of conductors and towers was designed independently. Because of the difficulty to calculate the longitudinal unbalanced tension of towers, it is generally verified by taking the percentage of the conductor maximum design tension according to regulations, However, the unbalanced tension is one of the important factors impacting the safety of transmission lines, so accurate calculating the longitudinal unbalanced tension caused by span, height difference, and uneven load is meaningful In this paper, the beam element and the cable element were used to establish integral unit model, spatial finite element calculation of icing load for transmission system was conducted, and the ultimate load-carrying capacity was calculated under the even ice load circumstance, and the causes for collapsed towers were analyzed under the condition of real uneven icing load. The weakness of the transmission line was pointed out and modification proposals were presented.