覆冰输电线的风致响应和脱冰分析

发布时间：2018-05-03 17:53

本文选题：非线性振动 + 覆冰输电线　；参考：《郑州大学》2014年硕士论文

【摘要】：高压输电塔线体系作为重要的生命线工程，保证其安全运行和防护意义重大。大跨度高柔性的输电线在风力作用下呈现明显的非线性振动特征，而在覆冰后该特性更复杂，受风力作用甚至会发生断线倒塔等事故，造成严重的社会和经济损失，因此针对覆冰后输电线在风作用下的非线性振动响应的研究，具有重要的理论意义和工程实用价值，可以为线路设计和安全运行提供有益参考和指导。论文首先总结了目前国内外针对覆冰线路动力分析的研究现状，包括对覆冰模型、倒塔、断线、脱冰冲击、舞动等理论与试验方法的研究和存在的问题，确定采用有限元方法进行覆冰输电线在风力作用下和脱冰冲击作用下的响应分析等工作内容，主要研究内容和结论如下：（1）输电线本身具有大跨度、高柔性特点，覆冰后输电线振动特性和风致作用下响应更具复杂性，在计算分析中主要考虑其几何非线性，首先推导了输电线覆冰前和覆冰后找形理论解析方法。（2）以柳东-桂林段500kV输电线路覆冰灾害事故为例，采用ANSYS软件建立跨度500m的四分裂导线-间隔棒体系有限元模型，通过对10mm、15mm、20mm和25mm厚度覆冰输电线找形计算结果与覆冰前的结果对比发现，，输电线的跨中垂度随覆冰厚度增加而急剧增大，线路运行张力也有大幅增加；当覆冰25mm时，计算跨中垂度已超出了输电线高度，输电线路已不能正常运行，虽然此时计算线张力并未超出设计运行张力上限值。（3）将覆冰四分裂导线-间隔棒体系模型简化为覆冰单导线模型，进行了等效有效性的分析和验算；进行了不同跨度、不同覆冰厚度、不均匀覆冰和不同覆冰模拟方法的模态分析，与输电线覆冰前进行对比，主要输出比较了不同参数组合下的振型和频率变化。（4）根据风场模拟技术，进行了不同风力、不同覆冰厚度和不同风攻角下输电线覆冰前后的时程分析，主要比较其跨中节点位移与加速度时程响应变化规律、端部节点张力时程变化特性，输出了不同工况组合下的加速度功率谱并分析其振动特性，结果表明：整体上覆冰厚度越大，风速越大，面内和面外耦合振动的幅值越大、能量越高，面外第一阶摆动对输电线实际振动形态的贡献最大。比较实际三维脉动风场和仅考虑顺风向脉动风情况下覆冰输电线响应结果，发现位移、加速度和线张力时程值相差很小，说明了目前线路规范设计中只考虑沿顺风向脉动风成分的做法是比较合理的。（5）基于输电线不均匀、不定期脱冰会引起导线大幅上跳甚至断线和线路倒塔等事故，本文还进行了10mm、15mm、20mm三种不同厚度覆冰导线全跨脱冰的瞬态动力分析和脱冰响应影响因素的分析，发现覆冰越厚，脱冰越集中，对线路危害越大；适当降低线张拉力和设置阻尼器等措施也可以有效削弱脱冰引起的影响。
[Abstract]:As an important lifeline project, it is of great significance to ensure the safe operation and protection of high voltage transmission tower system. The large span and high flexibility transmission lines show obvious nonlinear vibration characteristics under the action of wind force, but after icing, the characteristics are more complicated, and wind force may even lead to accidents such as broken lines and inverted towers, resulting in serious social and economic losses. Therefore, the study of nonlinear vibration response of ice-coated transmission lines under the action of wind has important theoretical significance and practical engineering value, and can provide useful reference and guidance for the design and safe operation of transmission lines. Firstly, this paper summarizes the current research status of dynamic analysis of icing lines at home and abroad, including the research and existing problems of icing model, tower, breakage, deicing impact, galloping and other theory and test methods. The finite element method is used to analyze the response of icing transmission lines under wind force and deicing impact. The main research contents and conclusions are as follows: 1) the transmission line itself has the characteristics of long span and high flexibility. The vibration characteristics and wind-induced response of the ice-coated transmission line are more complicated. The geometric nonlinearity is mainly considered in the calculation and analysis. Firstly, the analytical method of shape finding before and after icing for transmission lines is derived. (2) taking the ice-covered disaster of 500kV transmission line in Liudong Guilin section as an example, the finite element model of 500m span four-split traverse spacer system is established by using ANSYS software. By comparing the shape finding results of 10 mm / 15 mm / 20 mm and 25mm thickness icing transmission lines with the results before icing, it is found that the midspan sag of transmission lines increases sharply with the increase of ice thickness, and the line running tension also increases significantly when the ice is covered with 25mm. The calculation of span sag has exceeded the transmission line height and the transmission line has been unable to operate normally although the calculated line tension does not exceed the upper limit of the design operation tension. The model of ice-coated four-split traverse and spacer rod system is simplified to the ice-coated single-wire model, and the equivalent validity analysis and checking calculation are carried out, and the different span and thickness of icing are carried out. The modal analysis of non-uniform icing and different icing simulation methods is compared with that of transmission lines before icing. The main output is compared with the modal and frequency changes under different parameter combinations. 4) according to the wind field simulation technology, the time-history analysis of transmission lines before and after icing with different wind force, different ice thickness and different wind attack angle is carried out. The characteristics of the end joint tension time history change, the acceleration power spectrum under different working conditions is outputted and its vibration characteristics are analyzed. The results show that the larger the ice thickness on the whole, the greater the wind speed, the larger the amplitude of in-plane and out-of-plane coupling vibration. The higher the energy, the most important contribution of the first order oscillation to the actual vibration shape of the transmission line. Comparing the response results of the actual three-dimensional pulsating wind field and the ice-coated transmission line only considering the downwind pulsating wind, it is found that the time history of displacement, acceleration and line tension is very small. It is reasonable to consider the pulsating wind component along the downwind direction in the design of the current line code. (5) because the transmission line is not uniform, the occasional deicing will cause the wire to jump sharply, even break the wire and the line tower, and so on. In this paper, the transient dynamic analysis and the analysis of the factors affecting the deicing response of three kinds of ice-coated conductors with different thickness are also carried out. It is found that the thicker the icing is, the more concentrated the deicing is, and the greater the harm to the line is. The effect of deicing can also be weakened by reducing the tension of wire and setting dampers.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM752

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