【作者】 范孜；

【导师】 郝淑英；

【作者基本信息】 天津理工大学 ， 机械设计及理论， 2012， 硕士

【摘要】 架空输电线路在覆冰、风等载荷的作用下，往往会发生舞动。舞动是一种低频大振幅的自激振动，持续时间长，会对电力系统造成严重的危害。本文的目的就是利用非线性动力学的理论研究导线的振动特性，并通过建立输电线的有限元分析模型模拟舞动的过程，研究风速、线路结构、金具等对舞动的影响，提出防舞的优化方案。根据弹性力学的原理，建立了覆冰导线面内舞动的连续体动力学模型。利用Galerkin积分方法，将偏微分方程转化为常微分方程，并对方程进行一阶模态截断，得到导线面内的单自由度振动方程。采用平均法，求解方程的一阶近似解，得到导线面内振动的稳态振幅以及振幅、张力与系统非线性瞬态固有频率的关系。本文研究了导线的初始张力及舞动的幅值对固有频率的影响，给出了输电线覆冰舞动时系统的非线性固有频率与舞动幅值及导线初始张力的关系，对输电线路舞动中出现的频率飘移做了定性分析。采用三维空间梁单元建立了覆冰分裂导线的有限元模型，并对输电线进行了静力找形和模态分析，用ANSYS参数化设计语言编写了导线在气动力载荷作用下舞动的计算程序，得到输电线舞动的时间历程曲线。研究了风速、档距等对输电线舞动振幅以及动态张力的影响。发现同档距的输电线随着风速的增大，导线舞动幅值会增大，导线的动态张力会增大，并且静平衡位置的动态张力值会增大；在相同风速下随着档距的增大，导线舞动幅值及静平衡时的动态张力值增大。基于MATLAB软件，对有限元分析得到的导线舞动时程曲线进行了频谱分析，研究了风速及档距对输电线舞动频率的影响，分析结果与解析结果相吻合，进一步证明了输电线在舞动过程中舞动频率随风速和档距而变化。该研究对防舞器的设计具有重要的指导意义和很高的应用价值。用ANSYS软件建立了单相以及三相四分裂输电线的有限元模型，计算了现有相间间隔棒布局对导线舞动的影响，发现间隔棒的有些布局不具有防舞作用，其余布局虽有防舞作用，但由于间隔棒布局只是依据经验，缺乏针对性及理论分析，无法获得最佳的防舞作用。本文根据频谱分析以及导线舞动的位移矢量图得到导线舞动的主振型，根据导线舞动的主振型对相间间隔棒的布局提出了优化方案，并对不同风速下的防舞效果进行了计算，验证了本文优化布局的防舞效果较原来的布局明显提高。本研究成果为输电线的防舞设计提供了依据。更多还原

【Abstract】 The overhead transmission lines are often in galloping under the action of the icing, windand other loading. The power system can be damaged seriously by galloping, which is a kindof vibration with large amplitude and low frequency and lasts long. The purpose in this paperis to study the vibration characteristics of transmission lines by nonlinear dynamics theory,and to simulate the galloping process, investigate the effect of wind velocity, line structureand electric power fittings on galloping through building the finite element model oftransmission lines, meanwhile, a optimization approach for preventing galloping is proposed.According to the principles of elasticity mechanics, a continuum dynamics model of icedtransmission line galloping in plane can be established. By Galerkin method, a set of partialdifferential equations are transformed to a set of ordinary differential equations which aresolvable, and the vibration equation of one degree-of-freedom in plane is obtained by makingthe first modal truncation to this equation. The steady amplitude and its relationship withnonlinear transient inherent frequency are obtained by average method to solve the equationsof the first order approximate solutions. The effect of initial tension and galloping amplitudeof the transmission line on the natural frequency is investigated deeply, proposing therelationship between nonlinear natural frequency and galloping amplitude during galloping oficed transmission line. A qualitative analysis is made towards frequency shift in galloping oftransmission line.Based on the finite element model of iced bundle conductors made by 3D beam elementin this paper, the static form-finding and modal analysis have been conducted. At the sametime, the time history curve of galloping transmission line is obtained by programming thecomputational code of transmission line under the action of aerodynamic load withemployment of ANSYS parametric design language. Through the investigation of effect ofwind velocity and span on the amplitude of transmission line and its dynamic tension, theresult shows that the galloping amplitude of transmission line with the same span and itsdynamic tension increase with the increasing of the wind velocity. A spectrum analysis basedon MATLAB software is done to the time history curve of the transmission line gallopingobtained by the finite element analysis, and the numerical results agree with the analyticalones. The results prove that the frequency of galloping of the transmission line during theprocess of galloping varies with the wind velocity and span.The study has important guidingsignificance and high value for anti-galloping design.The finite element model of the single-phase and three-phase quad-bundle conductor isestablished based on ANSYS software, analyzing the effect of existing interphase spacerlayout on transmission line galloping and effects of the preventing galloping, which werefound that some layouts can not prevent galloping, the others can prevent galloping. These layouts are based on experience, lack of relevance and theroretical analysis,can not get thebest effect of anti-galloping. The vibration mode is obtained based on spectral analysis andthe displacement vector of conductor galloping. Optimization scheme is proposed accordingto the vibration mode and the effect of anti-galloping under different wind speed is calculated.The effect of anti-galloping of optimization scheme is better than the original layouts. Thestudy provide a basis for anti-galloping of transmission line.更多还原