湖州地区输电线路防雷分析

论述了湖州地区历年来的雷击及线路跳闸情况,并对雷击输电线路的原理以及采取相应有效的防雷措施及效果进行分析.     

基于小波分析的输电线路故障测距

通过分析输电线路故障暂态行波的折反射原理,得出了到达检测点的所有可能的行波信号,创新性的提出了各种行波的特点及其区别方法,并利用小波分析对局部变信号或微弱变化信号处理上的优势,提出了一种单端行波故障测距方法.与以往的测距方法相比,该测距方法具有硬件投入不少、不受双端同时钟的影响、测距误差小等优点.     

基于GIS的三维输电线路系统设计

根据三维GIS的技术特点和输电线路管理的需求,利用三维模型构建、模式设计和OGRE图形渲染引擎技术,结合虚拟现实和GIS的技术特点,实现用户在三维空间中认识和管理输电系统,使信息管理与维护更直观方便。     

输电线路中的造价管理分析

本文首先探讨了输电线路造价管理的定义与特点,结合实际介绍了衡阳电建公司某110KV输电线路工程造价管理的现状,着重对工程决策阶段、设计阶段、竣工阶段造价管理的影响因素进行分析,提出了相应的对策措施,对输电线路工程造价管理具有一定的借鉴意义。     

高压输电线路绝缘子防污闪措施分析

文章根据笔者多年实际工程经验,从多个方面分析了输电线路绝缘子防污闪的主要措施,指出应该以"三通一标"和"两型一化"等为指导进行绝缘子防污闪研究工作,为广大电力从业者提供了有益的参考.     

138kV输电线路连续倒塔原因分析

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.     

基于MLP法的磁浮列车非线性系统的稳定性分析

以磁浮列车的垂向运动为研究对象,研究其非线性系统的稳定性。选取气隙值、电流值为磁浮列车悬浮系统的广义坐标,依据拉格朗日-麦克斯韦方程建立磁浮列车非线性悬浮系统的动力学模型,得到的振动方程是三阶的强非线性负刚度微分方程。应用MLP法求得系统的共振永年项条件,并对初始方程进行了数值计算,得到了磁浮列车在空载、满载、过载情况下的悬浮系统振动时间响应曲线和相图,结果表明:随着列车质量的增加,列车初始位移增加,但列车启动后50 s的时间内,系统振动趋于稳定。     

输电线路鸟害分析及其防治措施

架空输电线路大多运行在荒山野外,无疑要受到鸟类活动的影响.通过对湖州地区鸟害的分析,结合其它单位防鸟害经验,提出输电线路防鸟害的措施.     

基于卷积神经网络的输电线路绝缘子缺陷检测

为精准识别绝缘子缺陷,引进卷积神经网络,设计针对输电线路中绝缘子缺陷的检测方法。引进区域建议网络概念,在有效目标区域内检索关键信息,确定图像中绝缘子所在位置的候选区域,使用计算机辅助绘图工具,分割该区域中的信息,提取信息中的有效信息,完成输电线路绝缘子图像采集与预处理;引进卷积神经网络,在Image Net中训练预处理图像,建立损失度函数,识别绝缘子缺陷特征;引进Sobel算子,在检测空间内布置若干个3×3的水平模板,沿垂直方向移动水平模板,实现对绝缘子破损的检测与定位。设计对比实验,实验结果证明：该方法可以在精准识别绝缘子弧环破损故障的同时,提高绝缘子缺陷故障检测结果的准确率。     

浅谈高压输电线路的运行与维护

随着电网建设的不断发展,高压输电线路规模越来越大,呈现点多、线长、面广的特点。在日常运行与维护中,线路上存在复杂的地形地貌、多样的气候和不断增加的外力破坏等诸多诱发因素,容易导致线路发生故障,造成重大经济损失和不良社会影响。因此,分析和研究高压输电线路各种运行故障的原因,并提出具体针对性措施,对提高线路供电安全性和可靠性很有必要。     

高压输电线路导线跌落非线性动响应分析(英文)

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.     

大变形空间曲梁有限元分析

为了进行空间曲梁大变形有限元分析,将直梁单元位移分量插值的思想改进为位移矢量插值用以建立曲梁单元的位移场,分别建立了适用于任意曲线形式的全拉格朗日和修正拉格朗日增量格式空间曲梁有限元列式.通过采用等参数曲线代替实际曲线的策略,使得修正拉格朗日增量格式曲梁单元可以应用于更广泛的场合.算例对比结果表明,曲梁单元的建立过程正确,曲梁单元的精度要明显高于直梁单元.一般情况下,仅用直梁单元数量1/5的曲梁单元就可以达到相同的计算精度.     

Numerical analysis on aeolian vibration of transmission lines with Stockbridge dampers

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.     

同轴电缆VOD系统信号传输过程中的噪声分析

本从VOD传输系统工作原理出发，对其下行传输噪声和上行传输噪声产生的机理进行了详细分析，从而为设计性能更加优化的相关系统提供了依据。     

Finite element study on impact sound transmission through a floating floor

To understand the characteristics of impact-sound transmission through a floor is very helpful for developing sound attenuation strategies to acquire a high quality of dwellings. Sound transmission through a floating floor to the room underneath was modeled by finite-element method (FEM). The sound pressure levels calculated by the FEM model on a scale of 1:4 was compared with the measured values, which demonstrate good agreement, particularly for impact sound of a relatively low frequency. The sound pressure level in a receiving room is strongly affected by the structural characteristics of both the floor and the room. The sound pressure transmitted through a clamped floor is lower than through a simply supported floor because of the larger rigidity of the clamped floor that contributes to the attenuation mechanism of stiffness. Increase in the thickness of the fiber-glass damping layer in the floor improves sound insulation. A larger room has a larger capacity to dissipate the sound pressure and thus has a lower sound pressure level. An asymmetric configuration of room avails sound attenuation because it has weaker structural and acoustic coupling than a symmetric one.     

双质点摩擦滑移隔震结构非线性分析

采用小波变换方法分析了双质点摩擦滑移隔震结构时频特性,结果表明：摩擦滑移隔震结构的动力特性与其运动形态有关,隔震层摩擦系数的改变对结构频率非线性影响较小,对阻尼非线性影响较大.     

A co-rotational updated Lagrangian formulation for a 2D beam element with consideration of the deformed curvature

A tensor-based updated Lagrangian （UL） formulation for the geometrically nonlinear analysis of 2D beam-column structures is developed by using curvilinear coordinates, which has considered the effects of the deformed curvature. Between the known configuration C1 and the desired configuration C2, a configuration C2^＊ derived by rigid-body motion of C1 is introduced to eliminate the element-end transverse displacements between C2^＊ and C2. A stiffness matrix is obtained in C2^＊; and then by a transformation defined by the element-end displacements, the stiffness matrix in C2^＊ is transformed into that in CI. Comparing the stiffness matrix with that in the conventional UL formulation for a 2D beam element, the initial displacement stiffness matrix emerges, which results from the deformed curvature within the element. Numerical examples have verified the accuracy and efficiency of the present formulation, and the results show that the deformed curvatures have significant effects when deformations are large.     

DC steady-states analysis of lossy uniform transmission lines

1 Introduction In the past 20 years with the rapid development of VLSI (very large scale integration) circuits and continual spread of electric power system scale, theories on transmission lines have become an important research field where finding the analytic solutions to lossy transmission line equations remains a tough nut. Since the mathematical tool cannot provide effective help, there is no universal method to solve transmission line equations [1]. A number of researchers have obtaine…     

Effects of un-transposed UHV transmission line on fault analysis of power systems

The conventional fault analysis method based on symmetrical components supposes that the three-phase parameters of un-transposed transmission line are symmetrical in case of fault. The errors caused by the method with the symmetrical distributed parameter circuit model as the equivalent circuit of the un-transposed ultra high voltage (UHV) transmission line were studied under both normal operation and fault, and the corresponding problems arising were pointed out. By contrast with electromagnetic transient and power electronics (EMTPE) simulation results with the asymmetrical distributed parameter circuit model of un-transposed line, it is shown that the conventional method cannot show the existence of negative and zero sequences before fault happening and there are many errors on voltage and current after fault happening which are different with fault types. The error ranges of voltage and current are 2.13%-81.13% and -7.82%-86.15%, respectively.     

合理应用消雷器降低线路跳闸率

本文分析了220KV朱陈线安装消雷器后,线路跳闸率的降低,肯定了使用消雷器后取得的防雷效果,并简述了消雷器保护范围及经济分析.