覆冰输电塔线体系风振响应数值模拟

输电塔线体系对风作用敏感,在冻雨区要考虑风和覆冰的共同作用.以常用输电塔5A-ZBC2为基础,综合已有资料,建立了输电塔线体系的覆冰模型.应用随机风振响应分析方法,分析了不同覆冰厚度和不同风速下的输电塔线体系的风振反应.结果表明:风速越大,随着覆冰厚度增加,塔顶位移最大值增大速度加快,脉动风作用效应明显;在较低风速下,随着覆冰厚度的增加,不平衡张力增大很不明显,而在较高风速下,随着覆冰厚度的增加,不平衡张力增加迅速;不均匀覆冰是导致输电线路不平衡张力迅速增加的主要原因;我国电力行业标准中关于纵向不平衡张力的取值偏于不安全,考虑覆冰和风荷载共同作用时应提高断线工况下不平衡张力设计值.

Numerical simulation on wind-induced vibration of iced transmission line systems

Transmission line systems(TLS) are vulnerable to winds and storms,particularly in cold climate regions where atmospheric ice accretes on network equipment.This paper describes a method for analyzing wind-induced vibrations of ice coating on transmission towers coupled with power lines.An ice coating model of TLS is introduced.Wind loads on ice coating TLS are also presented.The time histories of wind speed acting on TLS are simulated with the harmony superposition method.Finally,the responses of TLS under different thickness of ice coating and different wind velocity are discussed.The results show that the displacement and unbalanced tension increase rapidly with the thickness of ice and wind velocity increasing.The nonuniform ice coating on the conductors is the main reason for unbalanced tensions increasing significantly.Chinese electric power industry standard on unbalanced tensions in the condition of wire breakage is unsafe and it should be improved.