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1.
提出一种新的同杆架设输电线路故障定位算法 .该算法仅使用本地端的电压电流采样数据 .算法模型利用了非故障线的信息 ,有效排除了故障电阻和负荷对故障定位精度的影响 .计算机数字仿真验证结果表明 ,该算法精度较高 相似文献
2.
Transmissionlinesformthebackboneofpowerutilityoperationsandachievethecontinuityofservicefromgenerat ingplantstotheusers.Linesaresubjecttomultifariouskindsoffaultsbecausetheyareexposedtotheelements .Thecausesoffaultaremultifarious .Linefaultmaybetriggeredbylight ningstrokes.Treesmayfallacrosslines .Fogandsaltsprayondirtyinsulatorsmaycausetheinsulatorstringstoflashover.Iceandsnowloadingmaycauseinsulatorstringstofailmechanically .Followingtheoccurrenceofalinefault,itisnecessaryforthemaintenance… 相似文献
3.
INTRODUCTIONTransmissionlinesofapowersystemaresubjecttomanykindsoffaults.Theprincipaltypesare :phase to earth ;doublephase to earth(phase phase earth) ;phase to phase ;three phase.Followingtheoccurrenceofatransmis sionlinefault,themaintenancecrewmustfinda… 相似文献
4.
An accurate algorithm for fault location of double phase-to-earth fault on transmission line of direct ground neutral system
is presented. The algorithm, which employs the faulted phase network and zero-sequence network as fault-location model in
which the source impedance at the remote end is not involved, effectively eliminates the effect of load flow and fault resistance
on the accuracy of fault location. The algorithm achieves accurate location by measuring only one local end data and is used
in a procedure that provides automatic determination of faulted types and phases, and does not require the engineer to specify
them. Simulation results showed the effectiveness of the algorithm under the condition of double phase-to-earth fault.
Project (No. 023801211) supported by the Key Science Foundation of Tianjin, China 相似文献
5.
Induction motor faults including mechanical and electrical faults are reviewed. The fault diagnosis methods are summarized. To analyze the influence of stator current, torque, speed and rotor current on faulted bars, a time-stepping transient finite element (FE) model of induction motor with bars faulted is created in this paper. With wavelet package analysis method and FFT method, the simulation result of finite element is analyzed. Based on the simulation analysis, the on-line fault diagnosis system of induction motor with bars faulted is developed. With the speed of broken bars motor changed from 1 478 r/min to 1 445 r/min, the FFT power spectra and the wavelet package decoupling factors are given. The comparison result shows that the on-line diagnosis system can detect broken-bar fault efficiently. 相似文献
6.
Collapses of transmission towers were often observed in previous large earthquakes such as the Chi-Chi earthquake in Taiwan
and Wenchuan earthquake in Sichuan, China. These collapses were partially caused by the pulling forces from the transmission
lines generated from out-of-phase responses of the adjacent towers owing to spatially varying earthquake ground motions. In
this paper, a 3D finite element model of the transmission tower-line system is established considering the geometric nonlinearity
of transmission lines. The nonlinear responses of the structural system at a canyon site are analyzed subjected to spatially
varying ground motions. The spatial variations of ground motion associated with the wave passage, coherency loss, and local
site effects are given. The spatially varying ground motions are simulated stochastically based on an empirical coherency
loss function and a filtered Tajimi-Kanai power spectral density function. The site effect is considered by a transfer function
derived from 1D wave propagation theory. Compared with structural responses calculated using the uniform ground motion and
delayed excitations, numerical results indicate that seismic responses of transmission towers and power lines are amplified
when considering spatially varying ground motions including site effects. Each factor of ground motion spatial variations
has a significant effect on the seismic response of the structure, especially for the local site effect. Therefore, neglecting
the earthquake ground motion spatial variations may lead to a substantial underestimation of the response of transmission
tower-line system during strong earthquakes. Each effect of ground motion spatial variations should be incorporated in seismic
analysis of the structural system. 相似文献
7.
The modern travelling wave based fault location principles for transmission lines are ana-lyzed. In order to apply the travelling wave principles to HVDC transmission lines, the special tech-nical problems are studied. Based on this, a fault locating system for HVDC transmission lines is developed. The system can support modern double ended and single ended travelling wave princi-ples simultaneously, and it is composed of three different parts: travelling wave data acquisition and processing system, communication network and PC based master station. In the system, the fault generated transients are induced from the ground leads of the over-voltage suppression ca-pacitors of an HVDC line through specially developed travelling wave couplers.The system was applied to 500 Kv Gezhouba-Nanqiao(Shanghai)HVDC transmission line in China. Some field op- eration experiences are summarized, showing that the system has very high reliability and accu- racy,and the maximum location error is about 3 km(not more than 0.3% of the total line length). Obviously, the application of the system is successful, and the fault location problem has finally been solved completely since the line operation. 相似文献
8.
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
9.
针对灾后输电铁塔的损坏情况及输电铁塔安全检测的需求,介绍了一种灾后输电铁塔损伤检测机器人攀爬越障部分的机构设计和各机构的工作原理,分析了该机器人攀爬越障部分的运动过程.通过Pro/E仿真模拟和慧鱼模型制作试验,证实该机器人能在输电铁塔上攀爬,可自主越障,具有良好工作性能.该机器人能替代人工上塔检修,提高检修工作安全性. 相似文献
10.
提出以计算机网络为基础的超高压输电线路的故障定位和录波系统，在结构上具有开放式的特点，可根据要求方便地接入扩建线路，并且高速网络数通讯使系统具有极好的实时性．文中重点论述了故障定位新方法，它不仅在线路故障定碍位的数学模型建立上考虑了超高压长距离线路的分布参数特性，并且在计算方法上计及故障线路两端故障电流的相位，经ＥＭＴＰ仿真及测试可证明所提出的综合方法对超高运长距离输电线路故障定位的精确性．论述了以计算机网络为基础的输电线故障定位和录波系统，给出了系统结构和主要特点，重点阐述了所提出的精确超高压长距离输电线故障定位的新方法。 相似文献
11.
XU Gao-xiong 《重庆大学学报(英文版)》2011,10(2):78-83
It is important for the safety of transmission system to accurately calculate single-phase earth fault current distribution. Features of double sided elimination method were illustrated. Quantitative calculation of single-phase earth fault current distribution and case verification were accomplished by using the loop method. Influences of some factors, such as single-phase earth fault location and ground resistance of poles, on short-circuit current distribution were discussed. Results show that: 1) results of the loop method conform to those of double sided elimination method; 2) the fault location hardly influences macro-distribution of short-circuit current. However, current near fault location is evidently influenced; and 3) the short-circuit current distribution is not so sensitive to the ground resistance of poles. 相似文献
12.
武欢 《河北能源职业技术学院学报》2013,(4):60-62
判断铁路电力线路故障方案是电气化铁道技术研究的一个重要内容,研究铁路自闭贯通线的故障判断方案具有重要实际意义.本文结合目前铁路现场的实际情况,在理论上分析了各种故障机理并总结故障的特点.然后针对理论分析得出的结论,提出了基于主站的故障判断方案. 相似文献
13.
复杂的配电网系统中,蝠鲼觅食优化算法存在后期搜索能力不足导致故障定位准确率下降的缺点。针对该问题,提出了一种基于阈值反馈蝠鲼觅食优化算法的多电源配电网故障定位方法。在确立适用于复杂多电源网络的故障定位数学模型的基础上,采用Limit阈值控制算法求得极值时的迭代次数;在算法位置更新阶段引入交流反馈机制,加快算法收敛速率;利用Sigmoid函数对算法进行二进制离散化,输出故障向量完成故障定位。在Matlab中建立故障定位仿真模型,对多种算法开展对比实验。结果表明,不同故障情况下,改进的配电网故障定位算法的定位速度与准确度均优于其他算法。 相似文献
14.
朱锡钧 《实验室研究与探索》1999,18(1):86-89,91
本文从一体化微机的由来阐明一体化微机给故障检测所带来的利弊,归纳了一体化微机的故障分类,论述了故障定位的主要思路;并从硬件和软件两个方面介绍了排除故障的基本方法。 相似文献
15.
Kinematic measures of children's reaching were found to reflect stable differences in skill level for planning for future actions. Thirty-five toddlers (18-21 months) were engaged in building block towers (precise task) and in placing blocks into an open container (imprecise task). Sixteen children were retested on the same tasks a year later. Longer deceleration as the hand approached the block for pickup was found in the tower task compared with the imprecise task, indicating planning for the second movement. More skillful toddlers who could build high towers had a longer deceleration phase when placing blocks on the tower than toddlers who built low towers. Kinematic differences between the groups remained a year later when all children could build high towers. 相似文献
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17.
孙群 《福建工程学院学报》2015,(3):298-306
福州古塔在建筑类型、材料、平面、塔基、层数、高度、斗拱、塔檐、门窗、佛龛、平座、塔刹以及塔心室等方面既保留了江南和中原地区古塔的部分建筑样式,又根据福州独特的地域特征,进行了一些改造,具有典型的闽都建筑文化风格,浓缩了福州古代工匠天才的智慧与精湛的技术,蕴含着极高的文物考古价值与人文观赏价值。 相似文献
18.
用时域有限差分法研究了光在部分无序二维光子晶体波导中的传播特性．结果表明：介质柱的位置和大小无序对光予晶体波导的透射特性都有影响．仅当它的位置无序变化时,高频段缺陷带对无序度最敏感;仅当它的大小无序变化时,处于低频段缺陷带的高频端对无序度更敏感．当它的位置和大小都无序变化时,它的透射特性比仅受位置无序或大小无序影响更显著． 相似文献
19.
快速准确地诊断出换相失败故障,对后期采取适当控制措施避免保护装置误动有重要意义。首先建立永富弱受端直流输电系统的 PSCAD 仿真模型,对不同故障条件下的直流线路短路故障和换相失败故障进行仿真;利用 FEEMD 对不同故障条件下逆变侧的电流线模信号进行分解,并取 IMF7-IMF10 分量求样本熵值;然后将归一化后的样本熵值作为 Elman 神经网络的训练集和测试集,利用 Elman 神经网络的输出诊断直流系统运行状态,即正常状态（0 0 1）、线路短路故障（1 0 0）、换相失败（0 1 0）。对不同故障条件下的线路故障和换相失败故障进行仿真,实验结果表明,在训练集较少的情况下,线路故障的识别率为 85.71,%、换相失败故障占比92.85%;随着训练集增加,基于 FEEMD 样本熵+Elman 神经网络的方法对换相失败和线路故障的识别率达到100%,能够准确判断出故障类型。 相似文献
20.
地质雷达方法可应用于直接确定浅层地基内的断层位置、走向、倾向和倾角4个参数,间接分析得到断层的落差,不能探明充填物的详细赋存状态。地质雷达对浅层地基内涵洞的探测易于实现。探测实例表明,地质雷达不破坏目标体,效率高,在浅层探测中具有较高的精度,与钻探资料相结合,对浅层地基中的断层及涵洞等地质异常可作出准确判断,从而指导工程设计。 相似文献