覆冰荷载下500kV输电塔架的力学性能研究

发布时间：2018-01-10 19:22

本文关键词：覆冰荷载下500kV输电塔架的力学性能研究　出处：《内蒙古科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：近年来，我国南方地区的冰冻灾害频发，使输电线路严重破坏，给经济发展造成了不可估量的损失。为降低冰冻灾害下输电塔发生倒塌的概率，保障输电线路的畅通运行，研究覆冰荷载下输电塔及输电塔-线体系的力学性能具有重要的意义。本文以500kV线路DFZ1猫头型直线塔为研究对象，采用等效密度法来模拟覆冰荷载，通过建立输电塔和“双塔三线”输电塔-线体系的有限元分析模型，研究了不同覆冰厚度、不同工况下输电塔的静力性能及其动力特性的变化情况，并通过考虑几何初始缺陷和材料非线性，得到了覆冰荷载对其承载能力的影响规律；分析了不同覆冰厚度、不同工况下输电塔-线体系的静力性能，并对相同档距与不同档距、同高程与不同高程的输电塔-线体系的受力特征进行了对比。结果表明：随着覆冰厚度的增加，输电塔杆件的应力呈增大趋势，而塔顶位移则随之减小；输电塔在承受无偏心荷载时的屈服荷载最大，在承受偏心荷载且扭转变形较小时的屈服荷载次之，承受扭转荷载时的屈服荷载最小；输电塔的频率及第一阶阵型的控制点的数值随覆冰荷载的增加而减小，频率的最大降幅达到32.6%；覆冰厚度的增加会导致输电塔的破坏形式由整体破坏转变为局部破坏，破坏位置由塔腿位置逐渐上移至导地线悬挂点位置，覆冰输电塔的屈服荷载亦随之有不同程度的降低，最大降幅达22.7%；输电塔的抗扭能力随覆冰厚度的增加而提高。在输电塔-线体系中，在相同档距内出现导地线覆冰增加时，输电塔发生向靠近重冰档一侧的弯曲变形，，且应力增长较快，远离一侧的应力增长较慢；在不同档距中出现导地线覆冰增加时，与档距相同的输电塔架相比，档距不同覆冰输电塔的应力和弯曲变形更大；在不同高程内，当低高程导地线覆冰荷载增大时，输电塔的应力增长大于同高程输电塔的应力的增长；当中间高程导地线覆冰荷载增大时，输电塔的应力增长与塔顶位移均大于同高程的增长。本文研究成果可为覆冰下输电塔架的可靠性研究提供理论依据，为输电塔设计规范的修订提供一定的理论支撑。
[Abstract]:In recent years, the southern region of China's frozen disasters, serious damage to the transmission line, causing immeasurable losses to the economic development. In order to reduce the probability of freezing disaster collapsed tower of power transmission, to ensure smooth operation of the transmission line, has important significance on mechanical properties of transmission tower and transmission tower line system of ice load next.
In this paper, 500kV DFZ1 cat head straight line tower as the research object, to simulate the ice load by using the equivalent density method, by establishing a finite element transmission tower and Twin Towers three line transmission tower line system analysis model of different ice thickness, the change of performance and dynamic characteristics of static force transmission tower under different conditions next, by considering the initial geometric imperfections and material nonlinearity, and obtains the influence law of ice load on the bearing capacity; different ice thickness is analyzed, the static performance of transmission tower line system under different working conditions, and the same distance and different gear span, compared with elevation and different elevation transmission tower line system of the force characteristics.
The results showed that with the increase of ice thickness, increases the stress of transmission tower members, while the top displacement decreases; the transmission tower under eccentric load when no yield load, under eccentric load and torsional deformation of low yield load time, under torsional load when the minimum yield load numerical control; transmission tower frequency and the first order formation decreases with the increasing of ice load, the biggest drop in frequency reached 32.6%; increase the ice thickness will lead to damage in the form of transmission tower by the overall destruction into the local damage, damage location by location is gradually moved to the tower leg wire hanging point the position, the yield load of icing transmission tower will have different degrees of reduction, the largest decline of 22.7%; transmission tower torsional capacity increased with the increase of ice thickness. In the transmission tower line system, in which With the wire icing in the span increases, the transmission tower to the bending deformation of heavy ice close to the side of the file, and the stress of rapid growth, away from the side of the stress of slower growth; appear in different spans in wire icing is increased, compared to the same transmission tower and span, stress and bending deformation. From the different icing transmission tower more; in different elevation, when low elevation guide wire increases ice load, transmission tower stress growth greater than the same elevation transmission tower stress increases; when the middle elevation guide wire increases ice load, transmission tower stress and displacement are top growth more than the same height growth.
The results of this study can provide a theoretical basis for the reliability study of transmission tower under ice cover, and provide some theoretical support for the revision of the design specification for transmission tower.

【学位授予单位】：内蒙古科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU347

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