高压输电线路风振动张力荷载的作用机理与评估方法

The essential of wind load of overhead high-voltage transmission lines on supported structure is the dynamic tension load effect induced by the significant vibration of lines under strong wind. With development in Chinese electric grid, transmission lines shows the higher overhead height, longer spans, more multi-splits, more multi-circuits trends, resulted in this load effect become more complex and extraordinary. However, due to the complexity of vibrations, and the stochastic and spatial correlation of wind load, current understanding of formation mechanisms of wind-induced tension force are still not clear, especially lack of the accurate calculation theories and reasonable evaluation methods. The object of this project is to study the stochastic aerodynamic fluctuation tension in large-span lines induced by wind. Using the of rigid force testing models and aerodynamic models in wind tunnel test, the aerodynamic parameters and the stochastic properties of the wind-induced aerodynamic tension responds in insulator-lines system are investigated. Based on the three-dimensional nonlinear continuous cable aerodynamic dynamics theories, the theoretical modal in time domain and analytical solutions in frequency domain on the tension load effects are deduced. Through the study on calculation theories and wind tunnel tests, the response mechanism, controlling factors and the variation regulars of wind-induced dynamic tension response are analyzed and revealed. Based on the above formation mechanism study, the corresponding evaluation theories and equivalent static load methods on wind-induced dynamic tension load effect of transmission line are deduced and proposed. This project will open a new avenue to solve the key issues and lay the theoretical and experimental basis on the wind resistance design of power transmission tower - line systems under strong wind loads.

输电线风荷载的实质是强风下线路大幅振动对杆塔的动张力作用。随着高压输电网向多分裂、大跨度、高架空、多回路方向发展，这种作用更为显著和复杂。但由于输电线结构自身特有的振动复杂性及风场的随机性与空间相关性，目前对其形成机制的认识尚未明确，尤其是缺乏完备的动张力计算理论及合理的荷载评估方法，这已成为当前线路抗风研究的发展瓶颈。本项目以导线风振随机动张力效应为研究对象，通过改进和完善刚性模型测力及气弹性模型动力风洞试验，逐步从单根、单相、空间多相导线三个层面，系统研究典型大跨绝缘子-导线系统的气动特性及随机动张力响应的规律；依据连续悬索动力理论，完成空间风振随机动张力荷载效应的时域理论计算及频谱解析方法的建模；继而在全面揭示动张力荷载内在形成机制、影响因素及变化规律的基础上，建立输电线路风效应评估理论及等效风荷载实用计算方法。项目研究将为解决高压输电线路抗风设计的关键问题提供新的途径、建立理论与试验基础。

输电线风荷载的实质是强风下线路大幅振动对杆塔的动张力作用。随着高压输电网向多分裂、大跨度、高架空、多回路方向发展，这种作用更为显著和复杂。由于输电线结构自身特有的振动复杂性及风场的随机性与空间相关性，目前对其形成机制的认识尚未明确，尤其是缺乏完备的动张力计算理论及合理的荷载评估方法，已成为当前线路抗风研究的发展瓶颈。项目以导线风振随机动张力效应为研究对象，通过改进和完善刚性模型测力及气弹性模型动力风洞试验，逐步从单根、单相、空间多相导线三个层面，系统研究典型大跨绝缘子-导线系统的气动特性及随机动张力响应的规律；依据连续悬索动力理论，完成空间风振随机动张力荷载效应的时域理论计算及频谱解析方法的建模；继而在全面揭示动张力荷载内在形成机制、影响因素及变化规律的基础上，改进和完善了输电线路风荷载效应评估理论和抗风设计的方法。研究内容主要包括（1）输电线体型系数的刚性节段测力试验研究；（2）标准缩尺比气动弹性模型的动力风洞试验研究（3）输电线风振动张力响应的时频域理论计算方法研究。项目的完成很大程度上拓展了现有的输电线力学性能的力学计算和分析方法，也推动了国际现有的索结构力学分析理论和试验方法的基础研究。该课题的完成为解决高压输电线路抗风设计的关键问题提供新的途径。