导线覆冰大跨越输电塔-线体系动力特性分析

大跨越输电塔-线体系对导线覆冰等环境荷载反应敏感,容易发生动态倒塌破坏。目前对线路覆冰下输电塔的振动问题虽然取得了一定的研究成果,但是线路覆冰下输电塔的动力特性规律尚需进一步研究。本文以实际工程为例,建立了大跨越输电塔-线体系数值分析模型,分析了导线划分精度对输电塔-线体系动力特性的影响,并在此基础上分析了导线覆冰对输电塔-线体系动力特性的影响。研究结果表明:导线划分精度对输电塔振动影响较大;导线覆冰不仅影响输电塔振动频率,而且对输电塔振型也有较大影响,尤其是对输电塔横担的振动影响更大。

Dynamic Property Analysis of Iced Long-span Transmission Tower-line System

For the transmission line tower with a big span,the ice formed by frozen rain coating on transmission line will arouse system response,which is liable to cause dynamic collapse of the tower-line system.Although some achievements have been obtained at present on the research of power transmission tower vibration under ice load,further efforts need to be made in order to acquire dynamic properties of power transmission tower on the same loading condition.In this paper,an analytical-numerical model of long-span transmission tower-line system is founded based on an actual project.The influence of meshing precision of transmission line finite element model on the dynamic properties of transmission tower-line system is analyzed,and analysis of dynamic properties of the system with iced transmission line is carried out.It is shown from the results that mesh accuracy of transmission lines has an obvious effect on dynamic properties of power transmission tower.Additionally,ice coating on transmission lines affects not only natural frequency of transmission tower-line system but also the mode shapes,especially vibration of cross-arms.