DYNAMIC RESPONSES OF TRANSMISSION TOWER-LINE SYSTEM UNDER ICE SHEDDING
DYNAMIC RESPONSES OF TRANSMISSION TOWER-LINE SYSTEM UNDER ICE SHEDDING
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DOI：
10.1142/s0219455410003579
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发表时间：
2010-09
影响因子：
3.6
通讯作者：
Fengli Yang;Jing-bo Yang;Jun-ke Han;D. Fu
中科院分区：
文献类型：
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作者：
Fengli Yang;Jing-bo Yang;Jun-ke Han;D. Fu
导线覆冰容易引发电气和机械事故，严重威胁输电线路的安全运行。本文在有限元分析软件Ansys中建立了杆塔-导线-地线-绝缘子系统的三维有限元模型，分析了输电铁塔-线路系统在不同情况下的覆冰动力响应。计算的跳跃高度与双跨导线模型的实验值符合得很好。融冰模拟中考虑了塔线耦合效应、融冰导线的相位组合、积冰厚度、融冰跨度以及高程差等多种因素。研究了各变量对跳跃高度、绝缘子端部荷载和输电杆塔受力的影响。对2008年发生覆冰事故的实际500kV输电线路段进行了融冰仿真。结果表明，当融冰量较大时，塔顶杆件在设计冰厚下的应力比超过极限值。对于顶相导线除冰，采用三角形排列的相间隔板，可以减小跳跃高度和绝缘子端部不平衡张力。塔架在设计冰厚荷载作用下处于安全状态。为防止融冰事故的发生，应采用相间隔板，并根据计算的绝缘子端部负荷值对塔顶薄弱构件进行加固。
Ice shedding from conductors may easily induce electrical and mechanical accidents, which cause a serious threat to the safe operation of transmission lines. In this paper, a 3D finite element model of tower-conductor-ground wire-insulator system was established in ANSYS, and the dynamic responses of ice shedding under different cases were analyzed for a transmission tower-line system. The computed jumping heights are in excellent agreement with the experimental values of a two span conductors model. Many variables were considered in the ice-shedding simulations that include tower-line coupled effect, phase combination of the ice-shedding conductors, thickness of the accreted ice, length of the ice-shedding span as well as elevation difference. Influences of all the variables on the dynamic responses of jumping heights, loads at the end of insulators and the forces of transmission tower were studied. Ice-shedding simulations of an actual 500 kV transmission line section which experience failure under ice shedding in 2008 were performed. The results show that stress ratios of members at the tower head under design ice thickness exceed the limiting values when the amount of shedding ice is large. For ice shedding at the top phase conductors, the jumping height and unbalanced tension at the end of insulator can be reduced by applying interphase spacers in triangular arrangement. The tower is in a safe state under the load of the design ice thickness. In order to prevent ice-shedding accidents, interphase spacers should be used, and the weak members at the tower head should be strengthened according to the calculated load values at the end of insulators.