共查询到19条相似文献，搜索用时 250 毫秒
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耿超 《临沂师范学院学报》2012,(6)
在输电导线覆冰后,不管是覆冰自然脱落还是人工除冰,都会对输电线路造成冲击.覆冰脱落会引起导线大幅跳跃,导致导地线间或导线档中空气间隙减小,严重时引起闪络,影响线路运行安全.本文以某110KV单管输电塔线路为背景,建立单管塔线体系有限元模型,采用生死单元法模拟脱冰,分析单管塔线体系在导线脱冰时的动力响应.计算结果表明,导线覆冰后体系的自振频率略低于覆冰前的频率,导线脱冰使得脱冰跨导线大幅跳跃,同时脱冰会使单管塔产生较大的顶部位移和底部弯矩,这两者都是由输电线路脱冰产生的纵向不平衡张力引起的. 相似文献
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为准确评估下击暴流作用下输电塔施工场地抱杆的安全性能,采用有限元方法分析了悬浮抱杆的风振响应特性.基于确定性-随机混合模型,通过改进的随机波数谱方法模拟移动下击暴流的全过程风速,计算得到了悬浮抱杆在下击暴流作用下的风振响应.结果表明：悬浮抱杆在移动下击暴流的作用下将发生大幅摆动,同时主体结构出现弯曲变形,其中抱杆中段的顺风向位移幅值可达1.388 m,外拉线拉力最大值为45.11 kN,承托绳的最大拉力为47.06 kN,悬浮抱杆主体结构的最大位移及拉线的最大拉力均在下击暴流中心距离悬浮抱杆1 100 m附近时出现.可见,下击暴流作用下悬浮抱杆易产生较大的风振响应,将对输电塔的施工安全产生不利影响,有必要采取相关的加固与减振控制措施. 相似文献
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《实验室研究与探索》2016,(5):123-126
提出了基于有限元分析的输电铁塔应力计算方法,并开发了输电铁塔实时应力计算系统。采用桁梁混合模型对输电铁塔进行建模,对铁塔结构进行离散化,以节点位移阵列作为未知量,与整体刚度矩阵,载荷阵列组成矩阵方程,采用置1法消除整体刚度矩阵的奇异性,运用高斯消元法求解节点位移矩阵,根据弹性力学中应力与位移的关系,给出各节点应力,最终求出铁塔受力情况。通过自主开发的输电铁塔实时应力计算系统反演了铁塔的倒塔事故。分析结果表明,该系统具有较高的计算精度,可用于输电铁塔实时应力计算。 相似文献
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张之 《世界华商经济年鉴·科学教育家》2013,(5)
在高压输电线路工程中,杆塔是线路本体造价的重要组成部分,而直线型铁塔的重量直接决定了线路的投资.本文通过对高压输电线路中直线塔常用塔型:猫头塔与酒杯塔的对比分析,提出了适用于新疆高压输电线路更为经济的酒杯型铁塔型式. 相似文献
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潘安平 《温州大学学报(社会科学版)》2001,14(3):84-87
本文通过对平面广告牌架结构受力情况的分析研究，一针对建筑结构荷载规范中不够明确的地方和广告牌架结构设计_中应注意的风振系数的计算提出自己的看法，为该类型结构的设计提供参考依据。 相似文献
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闫亮 《湖州师范学院学报》2011,(Z1):1-3
电气几何模型(EGM)是计算线路绕击跳闸率的主要方法.本文在介绍电气几何模型原理的基础上,通过实证分析,研究输电线路直线塔绕击跳闸率,最后给出满足防雷要求的杆塔选型建议. 相似文献
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输电线路是一种重要的生命线工程,一旦发生破坏将给国家和社会带来巨大的经济损失,甚至危及人民的生命安全.以遭受强台风“海燕”袭击破坏的138 kV双回路输电线路为研究对象,结合现场勘测情况和数值分析结果,探讨该线路的倒塔原因.分析与对比表明:该输电线路灾害的主要原因是输电塔结构设计承载力不足,在台风过境时结构无法承受外荷载,最终导致线路的大面积倒塔和长时间的电力中断. 相似文献
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高压输电线路导线跌落非线性动响应分析(英文) 总被引：1，自引：0，他引：1
为了研究机械性故障对高压输电线路耦合体系的受力影响,建立了输电线路耐张段的非线性耦合体系模型,通过导线找形非线性静力计算确定了耐张段的初始平衡状态.采用瞬态动力分析方法计算了导线、绝缘子破坏失效危险工况下的输电线路耦合体系非线性动响应.分析结果表明,上横担一组导线断裂失效对邻近端导线张力没有明显影响,对邻近端的绝缘子及铁塔横担构件的受力有较大的影响;上横担一组绝缘子破坏失效后,破坏档未破坏端导线的张力超过了技术规程中的设计值;导线的跌落对破坏档未破坏端的上横担绝缘子受力有较大的影响,而对上横担铁塔杆件没有明显的影响;在架空送电线路的设计中应该考虑绝缘子断裂的荷载工况.研究成果可为输电线路结构设计提供理论依据. 相似文献
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We investigated wind-induced vibration control of long-span power transmission towers based on a case study of the Jingdongnan-Nanyang-Jingmen 1 000 kV transmission line project in P. R. China. The height of the cup tower is 181 m with a ground elevation of 47 m, which makes it a super flexible and wind-sensitive structure. Therefore, we should analyze the wind- resistant capacity of the system. We simulated applicable transverse fluctuating wind velocity field, developed a lead-rubber damper （LRD） for controlling wind-induced vibration of long-span transmission towers, deduced LRD calculation model parameter, and researched the best layout scheme and installation method of LRD. To calculate the wind-induced response of tower-line coupling system in seven layout schemes, we used the time history analysis method, and obtained the efficiencies of wind-induced vibration control. LRD deformation research proved that the damp of all LRDs was efficient under the designed wind velocity when they were laid along the edge of tower heads. We studied the controlling efficiency resulting fTom only applying stiffness to the tower polos where the dampers used to be laid under the designed wind velocity. The results show that the controlling efficiency was not ideal when the stiffness is increased on the poles only. Therefore, LRD should conlxibute to both the stiffness and damp of a structure to effectively reduce the dynamic response of a tower-line coupling system under strong winds. We also discussed the controlling efficiency of LRD under static winds. The results show that there was little difference between displacements derived by the finite clement time history method and those obtained by static wind method conducted by a design institute. This means the simulation on space relevant wind velocity field was accurate and reasonable. 相似文献
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为研究拱型波纹屋盖在脉动风作用下的应力风振系数,考虑不同跨度、支座、不同矢跨比对应力风振系数的影响,利用ANSYS有限元分析软件对18 m、30 m跨波纹拱进行水平及竖向脉动风作用下的风振响应分析,得到了结构在不同位置处节点的应力及应力风振系数.计算结果表明:波纹拱应力风振系数随着结构的跨度增大而增大,随着矢跨比的增加而增加,支座约束为固支波纹拱的风振系数小于铰支波纹拱.该结论为结构设计、施工及同类型大跨轻型屋盖的风致振动提供参考和借鉴. 相似文献
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We used computational fluid dynamics （CFD） and mode superposition method instead of the energy balance method to compute transmission line aeolian vibrations induced by the Karman vortex. Firstly, we obtained the wind power inputs using CFD theory. The result is effective for aeolian vibration analyses compared with the power which were measured in wind tunnel tests. Then a new aeolian excitation was derived using the wind power equivalent principle, and the aeolian vibration distribution along transmission lines and the wind power input obtained by CFD can be account. Secondly, we formulated the motion equation of a conductor-damper system and derived a semi-analytial solution using the mode superposition method. The Stockbridge-type dampers attached were simplified to the forces transmitted by the clamps. Finally, the semi-analytical solution can be solved by iterative methods. Taking a 1 000 kV Ultra High Voltage transmission line as an example, we analyzed the line with and without dampers by the semi-analytical solution. Compared with the results which were computed by the energy balance method, the semi-analytical solution is precise enogh for aeolian vibration analyses. Besides, we also analyzed the influence of damper position and quantity. 相似文献
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JIANG Zhi-chao DOI Yasuaki ZHANG Shu-you 《浙江大学学报(A卷英文版)》2007,8(9):1414-1421
Straight Darrieus wind turbine has attractive characteristics such as the ability to accept wind from random direction and easy installation and maintenance. But its aerodynamic performance is very complicated,especially for the existence of dynamic stall. How to get better aerodynamic performance arouses lots of interests in the design procedure of a straight Darrieus wind turbine. In this paper,mainly the effects of number of blades and tip speed ratio are discussed. Based on the numerical investigation,an assumed asymmetric straight Darrieus wind turbine is proposed to improve the averaged power coefficient. As to the numerical method,the flow around the turbine is simulated by solving the 2D unsteady Navier-Stokes equation combined with continuous equation. The time marching method on a body-fitted coordinate system based on MAC (Marker-and-Cell) method is used. O-type grid is generated for the whole calculation domain. The characteristics of tangential and normal force are discussed related with dynamic stall of the blade. Averaged power coefficient per period of rotating is calculated to evaluate the eligibility of the turbine. 相似文献
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Long span ultra-high voltage （UHV） transmission lines have serious aeolian vibration problems. To control these vibrations, we improved the energy balance method in the following aspects： the wind power input, the conductor self-damping, and the damper dissipated power. Meanwhile, we built a theoretical mechanical model of β wire dampers and derived energy dissipation calculation formulae. This permits the vibration energy dissipated by β wire dampers can be considered in the energy balance method. Then, we developed a computer program based on the improved energy balance method using Matlab, and analyzed UHV long span ground wires of the Han River long span project in P. R. China. The results show that the combination of β wire dampers and Stockbridge dampers can reduce vibration of UHV long span transmission lines, which provides a reference for research and construction of UHV engineering projects. 相似文献
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强度和振动特性是设计塔式起重机的金属结构的重要指标。利用有限单元法进行塔式起重机的整体建模,分析了塔式起重机的强度特性和振动特性,指出了极限吊重情况下静态极限强度的位置,并分析了塔式起重机的振动频率和振型,为研究塔式起重机的其他动力响应提供了依据。 相似文献
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针对高校新能源、电气和自控专业学生普遍缺乏针对风力机叶片振动控制的实践环节,提出了基于LabVIEW的风力机叶片振动特性与控制仿真实验设计方案,该方案利用LabVIEW搭建了风力机叶片的经典颤振模型,建立叶片振动特性与控制仿真实验系统。整个仿真实验系统,可在多种典型风速场景下进行叶片振动特性实验,同时,可自行设计控制参数,进行叶片PID振动控制和自适应振动控制的仿真。通过直观的虚拟仿真交互系统,有效克服了场地和设备带来的时间、空间上的局限,促进学生对于风力机叶片振动特性的了解,增强了叶片振动控制设计的实践能力。 相似文献
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方小兵 《五邑大学学报(社会科学版)》1992,(1)
本文采用矩阵传递法分析了调频质量阻尼器(TMD)被动控制高层建筑风振反应,导出了结构顶层位移、加速度和基底剪力频域内统计特征公式。最后通过实例的结果说明,经过控制后能显著地降低风振反应。 相似文献