覆冰输电线路舞动试验研究和非线性动力学分析

发布时间：2018-06-25 12:17

本文选题：覆冰 + 舞动　；参考：《浙江大学》2014年博士论文

【摘要】：舞动是导线覆冰后在风荷载作用下产生的自激振动。舞动对输电线路危害极大,引起的动张力会造成相间闪络、导/地线断股、间隔棒撕裂等事故。尤其是在特定气象条件下,导线舞动的持续时间可长达几天,从而有可能导致杆塔构件撕裂、失稳甚至倒塔等事故的发生。近年来,随着我国电网规模的迅速发展和恶劣气候的频繁出现,电力系统发生舞动事故的频率和对电力行业的危害程度呈显著增加的趋势,严重威胁着电力能源的正常输送和国民经济的稳定发展。因此,深入开展覆冰输电线路舞动的试验研究和理论分析、完善输电线路抗舞设计方法和提供相关技术支撑和科学依据,有着十分重要的工程意义和经济价值。本文的研究工作主要包括以下几个方面： 1.覆冰输电线路静张力对横担作用特征的研究：以在线路覆冰作用下横担严重破坏的转角耐张塔为研究对象,制作大比例输电塔节段模型,并按相似理论设计、加工了覆冰导线模型,对输电塔进行了模拟导线重覆冰状态下的静力加载试验。同时考虑连接偏心、节点板和螺栓长度等细节对构件传力路径的影响,建立了精细化的中横担有限元模型,对静力试验进行全过程的数值模拟,并与关键截面处的荷载-变形特征试验结果进行对比。在此基础上通过非线性屈曲计算,考察了覆冰导线静张力作用下横担的失效模式及薄弱环节。 2.输电塔线体系舞动响应和杆塔失效机理的试验研究：以在舞动事故中横担严重破坏的某转角耐张塔研究对象,基于模型动力相似原理,设计制作了弹性边界条件下的大比例输电塔节段模型和能够模拟不同覆冰参数的导线模型,并首次研制开发了模拟覆冰导线舞动的试验加载装置。在此基础上,于试验室条件下再现了导线舞动时的动张力和运动特征,并进行了不同参数下的输电塔线体系舞动试验,研究了覆冰厚度、舞动幅值以及频率对塔线体系响应特征的影响。同时,结合实际线路舞动时的特征参数,于试验室条件下进行了覆冰塔线体系舞动事故的反演,并根据试验测得的构件动应力幅值,计算了输电塔构件在导线舞动作用下的疲劳寿命。最后,综合分析塔线体系舞动试验和疲劳寿命的计算结果,揭示了舞动作用下输电杆塔失效的根本原因。 3.覆冰输电线路舞动非线性动力学与双参数分岔分析：建立了考虑竖直向、水平向和扭转向三维非线性耦合效应的连续体覆冰分裂导线舞动方程,并根据Galerkin积分和Routh-Hurwitz稳定性判据准则标识系统在参数空间中的稳定域和非稳定域。在此基础上,选定风速、初始风攻角以及竖向阻尼比为分岔参数,应用中心流形降维方法求解了原系统在平衡点附近的约化系统。通过将分岔参数视为系统状态变量的方式,把含参数的约化系统转化为不含参数的扩张系统,并利用规范形理论分段求解了扩张系统的Hopf分岔规范形,研究了双参数同时变化对导线舞动响应的影响。 4.分裂导线舞动非线性数值模拟：基于完全拉格朗日格式,建立了适用于单导线和分裂导线舞动数值模拟的非线性有限元舞动分析方法。采用具有扭转自由度的三节点抛物线索单元离散覆冰单导线。对于覆冰分裂导线,在单导线有限元法的基础上,利用欧拉梁单元模拟间隔棒的运动过程,结合梁节点弯曲自由度缩聚法实现了间隔棒与分裂子导线之间的耦合,并运用随转坐标系求解舞动过程中的梁节点不平衡力。在此基础上,结合覆冰分裂导线气动力测试结果,研究了风场特性、导线覆冰厚度和初始凝冰角对输电线路起舞机理和响应特征的影响。 5.三维瞬态风场下覆冰导线舞动数值模拟：根据随机流场生成方法和三维风速功率谱,逐点模拟了覆冰分裂导线周边的脉动风速场,并从瞬态流场的不可压缩特征、风功率谱、时间相关函数以及空间相关系数等统计特征证明了风场模拟方法的有效性和合理性。运用分裂导线舞动非线性有限元法对输电线路在均匀流场、一维脉动风速场和三维瞬态风场下进行了舞动瞬态分析,在此基础上讨论了风速场瞬态效应对舞动响应的作用机制,
[Abstract]:Dancing is the self excited vibration produced by the wind load after the wire is covered with ice. The dance movement is very harmful to the transmission line, and the dynamic tension will cause the interphase flashover, the guide / ground broken strand, the interval rod tear and so on. Especially in the specific weather conditions, the duration of the traverse movement can last for several days, which may lead to the tearing of the tower members. In recent years, with the rapid development of the scale of the power grid in China and the frequent occurrence of bad weather, the frequency of the dancing accidents in the power system and the damage to the power industry have increased significantly, which seriously threatens the normal transmission of power energy and the stable development of the national economy. It has very important engineering significance and economic value to carry out the experimental research and theoretical analysis on the dance of icing transmission lines, improve the anti dance design method and provide the relevant technical support and scientific basis. The research work of this paper mainly includes the following aspects:
Study on the effect of static tension on 1. ice covered transmission lines: a large proportion transmission tower segmental model is made with a large proportion of the transmission tower segment model under the action of the line icing, and the ice covered wire model is designed according to the similarity theory, and the static loading of the transmission tower under the state of simulated ice overburden is carried out. At the same time, considering the influence of the connection eccentricity, the length of the joint plate and the length of the bolt on the force transmission path, a finite-element model of the medium transverse load is established, and the numerical simulation of the static test is carried out in the whole process, and the results are compared with the test results of the load deformation characteristics at the key section. On this basis, the calculation of the nonlinear buckling is calculated. The failure modes and weak links of the cross arm under the action of static tension of iced conductor are investigated.
2. experimental study on the dynamic response of transmission tower line system and the mechanism of tower failure: Based on the model dynamic similarity principle, a large proportion transmission tower segment model under elastic boundary conditions and a wire model which can simulate different icing parameters are designed and made. On the basis of this, the dynamic tension and motion characteristics of the traverse were reproduced on the basis of the test room, and the dynamic test of the transmission tower line system under different parameters was carried out, and the influence of the ice thickness, the dance amplitude and the frequency on the response characteristics of the tower line system was studied. At the same time, combined with the characteristic parameters of the actual line dance, the inversion of the dance accident of the ice tower line system was carried out under the test room condition, and the fatigue life of the transmission tower members under the action of wire was calculated according to the amplitude of the dynamic stress measured by the test. Finally, the danced test and fatigue life calculation of the tower line system were analyzed. As a result, the root cause of failure of transmission tower is revealed.
The nonlinear dynamics and two parameter bifurcation analysis of 3. ice covered transmission lines: a continuum ice cladding line dance equation with vertical, horizontal and torsional steering nonlinear coupling effects is established, and the stable domain and instability of the system in parameter space are identified according to the Galerkin integral and the Routh-Hurwitz stability criterion. On this basis, the wind speed, the initial wind attack angle and the vertical damping ratio are selected as the bifurcation parameters. The reduction system of the original system at the equilibrium point is solved by using the central manifold dimension reduction method. By considering the bifurcation parameters as the system state variables, the reduction system containing parameters is converted into an expansive system without parameters. The normal form theory is used to solve the Hopf bifurcation normal form of the expansion system piecewise, and the influence of the simultaneous change of two parameters on the galloping response of the conductor is studied.
Nonlinear numerical simulation of 4. split traverse Dance: Based on the complete Lagrange scheme, a nonlinear finite element dance analysis method for numerical simulation of single wire and split traverse is established. A three node parabolic cable unit with torsional degrees of freedom is used to disperse the ice single wire. For ice clad traverse, the single wire is limited. On the basis of the element method, using the Euler beam element to simulate the motion process of the spacer, the coupling between the spacer and the split sub wire is realized by the bending free degree condensation method of the beam node, and the unbalance force of the beam node in the process of dancing is solved by the coordinate system. On this basis, the aerodynamic test results of the ice covered split lead are studied. The influences of wind field characteristics, conductor icing thickness and initial ice condensing angle on the transmission mechanism and response characteristics of transmission lines are studied.
5. numerical simulation of ice covered traverse in three dimensional transient wind field: Based on the random flow field generation method and the three-dimensional wind power spectrum, the fluctuating wind velocity field around the ice covered split wire is simulated point by point, and the wind field model is proved from the incompressible characteristics of the transient flow field, the wind power spectrum, the time correlation function and the spatial correlation coefficient. The validity and rationality of the proposed method. The transient analysis of transmission lines under uniform flow field, one dimensional fluctuating wind field and three dimensional transient wind field is carried out by using the nonlinear finite element method of split wire dance. On this basis, the mechanism of the transient effect of wind field on the dynamic response of the transmission line is discussed.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM75

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