【作者】 孙珍茂；

【导师】 楼文娟；

【作者基本信息】 浙江大学 ， 结构工程， 2010， 博士

【摘要】 覆冰输电导线在一定风速下常发生舞动,它是一种低频率、大振幅的自激振动。舞动的振幅通常很大,对输电线路的安全运行具有很大的威胁。随着电力建设的大规模发展,对舞动的深入研究是一项十分紧迫的任务。本文从舞动响应的模拟及防舞技术两方面对舞动进行了研究,论文的主要研究内容和成果有：利用拉格朗日方程推导了装有压重或者失谐摆防舞器的覆冰导线统一的非线性运动微分方程组；利用Runge-Kutta方法求解该微分方程组,得到了导线舞动响应的数值解；将导线所受气动力用泰勒公式展开到第三阶,用平均法求解简化后的微分方程组,得到舞动响应的简化解析解。根据微分方程稳定性理论提出了舞动临界风速的计算方法。推导了分裂导线扭转刚度的计算公式。得到的主要结论有：扭转角小于90°时,分裂导线扭转刚度大致为常数,可用初始扭转刚度作为分裂导线的扭转刚度；单导线只有当风速位于某一范围时才舞动,而分裂导线只要风速超过临界风速就必定会舞动,不会出现风速过大舞动停止的现象；单导线和分裂导线舞动振幅与导线跨中垂度的关系是相似的,两者都存在一个最不利的跨中垂度使舞动振幅最大；单导线舞动振幅存在最不利的档距,而分裂导线的振幅则随着档距的增大而增大。推导了考虑导线扭转自由度的三节点索单元的单元质量矩阵以及刚度矩阵,编制了计算导线舞动响应的非线性有限元程序。建立了塔线耦联的有限元模型,研究了输电塔对舞动的影响。用谐波叠加法模拟了考虑空间相关性的人工风速时程,研究了风速脉动及空间相关性对舞动的影响。得到的主要结论有：非线性有限元方法模拟得到的横风向舞动向上振幅比线弹性方法向上舞动振幅略大,而向下舞动的振幅却略小；舞动时导线的最大动张力要大于导线的静张力,单导线的最大动张力随着风速增大先增大后减小,存在最大值；而分裂导线的最大动张力则随风速增大而增大；输电塔对舞动振幅略有影响,其影响的幅度与风速有关；考虑风速脉动后导线舞动振幅略有增大。研究了新型液体阻尼器的设计及其防舞效果,研究了压重防舞器及失谐摆在单导线和分裂导线上的防舞效果。得到的主要结论有：按照本文提出的方法设计的新型液体阻尼器的防舞效果较好,若设计参数不当,新型液体阻尼器的防舞效果则不太理想；压重防舞器在单导线上效果较好,在分裂导线上效果较差；失谐摆在单导线上非常有效,在分裂导线上效果甚微。利用风洞试验实测了新月形覆冰导线及装有不同直径的扰流防舞器覆冰导线的气动力系数曲线,利用CFD技术数值模拟了扰流防舞器的气动力系数曲线,研究了扰流防舞器覆盖率与舞动振幅的关系,得到的主要结论有：各种直径的扰流防舞器都具有一定的防舞效果,直径0.75D的扰流防舞器防舞效果最佳；当扰流防舞器的覆盖率达到30%以后,覆冰导线的舞动可以得到完全抑制。更多还原

【Abstract】 Under certain wind velocity, iced transmission line often occurs galloping, which is a low frequency and large amplitude self-excited vibration.The galloping amplitude is usually large,which is a very big threat to the safe operation of the transmission line. With the construction of large-scale power development, studying deeply in galloping is a very urgent task.The galloping response simulation and galloping prevention was studied in this paper. The paper’s main contents and results are:The uniform nonlinear dynamic differential equations of iced transmission line installed with weighting and detuning pendulum was derived using Lagrange Method. The differential equations were solved by Runge-Kutta Methods and the Average Method respectively to obtaine numerical and analytical solutions of galloping response.The formulas for critical wind speed and torsional stiffness of bundled transmission lines were presented. The main conclusion are:When the torsional angel is smaller than 90 degrees,the torsional stiffness of the bundled lines is constant,which can be used as the initial torsional stiffness.The single line can gallop in a certain range of wind speed,while the galloping amplitude of bundled lines increases with wind speed.The relationship between galloping amplitude of single line and bundled lines with sag are similar,both exist a worst sag to cause maximum galloping amplitude.The single line exist a worst span to cause maximum galloping amplitude,while the galloping amplitude of bundled lines increases with the span.The mass element matrix and stiffness element matrix of the three degrees cable element considered torsional degree was derived.The nonlinear finite element program to calculate galloping amplitude was designed.The coupled FEM model of tower and lines was set up.The impact of tower to line galloping was studied. The impact of velocity fluctuation and spatial correlation to galloping was researched.The main conclusions are:The upward tranverse galloping amplitude is larger by nonlinear FEM than by linear FEM,while the downward amplitude is reverse.The tension of galloping lines is larger than static lines.The tension is 15% more in galloping single line than in static line.The tension of bundled lines increase with wind speed,and when wind speed is 20m/s,the tension increases 25%.There is a slight impact of tower on galloping amplitude,and the impact is related with wind speed. The galloping amplitude increases slightly considering the velocity fluctuation.A new type of liquid damper was designed and its anti-galloping performance was studied.The effects of weight and detuning pendulum installed on single line and bundled lines were researched. The main conclusions are:If the new type of liquid damper was designed by the proposed method in this paper, its anti-galloping effect is good. If the design parameters are not appropriate, the anti-galloping effect is less satisfactory.The anti-galloping effect of weight is good for single line and less effective for bundled lines. The detuning pendulum is very effective in a single line, but little effective in bundled lines.The aerodynamic coefficient curves of iced transmission line, transmission line installed with air flow spoiler without ice and iced transmission lines installed with air flow spoiler were measured by wind tunnel test. The aerodynamic coefficient curve of air flow spoiler was simulated by CFD.The relationship between the air flow spoiler coverage with galloping amplitude was researched. The main conclusions are:All the air flow spoilers of different diameters have certain effects to prevent galloping and the air flow spoiler of 0.75D diameter has the best effect to prevent galloping.When the coverage of air flow spoiler is 30%, the galloping can be inhibited completely.更多还原