Research on Evaluating Index of Lightning Protection Safety Performance of High Voltage Overhead Transmission Line

In order to improve the lightning protection performance of transmission lines, lightning protection management has been divided into every tower that lightning protection performance has been evaluated respectively. According to factors such as landform, span, tower type, grounding resistance, isolator type, and so on, relative ratio of tripping operation of every tower in the line has been calculated to evaluate its lightning protection safety performance, it is beneficial to operation maintenance and lightning reconstruction of transmission lines.

CHARACTERISTICS ANALYSIS OF THE INDUCED OVERCURRENT GENERATED BY CLOSE TRIGGERED LIGHTNING ON THE OVERHEAD TRANSMISSION POWER LINE

Techniques of artificially-triggered lightning have provided a significantly useful means to directly measure various physical parameters of lightning discharge and to conduct research on protection methods of lightning electromagnetic pulses.In this study,using capacitive and resistive dividers,current probes and optical fiber transmission devices,we measured and analyzed the induced overvoltage on the overhead transmission line and the overcurrent through Surge Protective Devices(SPD) when a lightning discharge was artificially triggered nearby on August 12,2008 at Conghua Field Lightning Experiment Site.The triggered lightning discharge contained an initial current stage and eight return strokes whose peak currents ranged from 6.6kA to 26.4kA.We found that overcurrents through SPD were induced on the power line both during the initial continuous current stage and the return stroke processes.During the return strokes,the residual voltage and the current through the SPD lasted up to the ms(millisecond) range,and the overcurrents exhibited a mean waveform up to 22/69μs with a peak value of less than 2kA.Based on the observed data,simple calculations show that the corresponding single discharge energy was much greater than the values of the high voltage pulse generators commonly used in the experiments regulated for SPD.The SPD discharge current peak was not synchronous to that of the residual voltage with the former obviously lagging behind the latter.The SPD discharge current peak was well correlated with the triggered lightning current peak and the wave-front current gradient.The long duration of the SPD current is one of the major reasons why the SPD was damaged even with a big nominal discharge current.

Research on Lightning Protection of Overhead Power Distribution Lines

There are two major protective methods against lightning outages on overhead distribution lines.One is a surge arrester,and the other is an overhead ground wire.The surge arresters have rather constant effect regardless of the cause of the lightning outage.On the other hand,the effect of an overhead ground wire is quite different in two major causes,the direct lightning hit and the induced overvoltage.It is sufficient to provide surge arresters with an interval of 300 m for protection against the induced overvoltage caused by the nearby lightning stroke.Use of an overhead ground wire together with surge arresters is effective for lightning protection against the direct lightning hit to a distribution line.Puncture of surge arresters is the popular outage when the outage caused by the insulation break decreases sufficiently.Also,the existence of nearby trees leads to the line break due to the side flash from a tree.Advanced lightning protection equipment with ZnO arrester components is popular in Japan.Modeling of a pole transformer and application of an electromagnetic analysis method,such as FDTD method,to surge phenomena is considerably advanced.

Process Analysis of Double Circuit Transmission Line Trip-out on the Same Tower Due to Lightning

In recent years,several failures of double circuit transmission line on the same tower due to lightning were happened in Beijing power grid.Although it can be reclosed successful,the lightning strike caused a grave threat to the power grid security.The cause of the accident and the accident process were studied for the sake of further understanding of the impact of lightning on power grid.As an example,110 kV double circuit transmission line(Xilong-line) was analyzed.At first,the system topology was given.Through the analysis on relay protection actions and the fault recorder data,over voltage on the insulator strings was calculated.Based on the analysis and the calculation,accident cause and the process were presented respectively.Secondly,it comes to the conclusion that the lightning failure was caused by counterattack.The wave of the lightning over voltage would spread to the not grounded neutral point of the transformers,and make the neutral protective gap breakdown,then cause freewheeling with the frequency of 50 Hz.As results of the relay protection,the double circuit transmission line all tripped out.Finally,the causes of the accident were proposed that included terrain features,large corner towers,strong thunderstorm weather and poor grounded contact of the tower.

Identification of Lightning Stroke and Fault in the Travelling Wave Protection

To resolve the impact of transient high frequency signals induced by lightning stroke on the travelling wave protection of transmission line, a novel identification algorithm is proposed. Using the characteristics of symmetric current wave-form induced by lightning stroke without causing fault and that of asymmetric current waveform generated by fault within a very short time interval, the waveform of transient current above and below time-axes are integrated respec-tively. First, through comparing the relative ratio of them with threshold value, the primary criterion identifying fault and lightning stroke is constructed;Secondly, to improve the reliability of discrimination between lightning stroke with and without causing fault, according to the difference of them, the secondary criterion is also defined. The simulation results and analysis demonstrate that the proposed integral criterions are valid and correct.

超/特高压输电线路雷电绕击分析方法及其适应性

输电线路雷击已成为制约电力系统安全可靠运行的首要因素,而500 kV及以上电压等级的输电线路主要以雷电绕击导线为主。该文在回顾电气几何模型发展历史的基础上,针对电气几何模型忽略大部分雷击物理过程的问题,详细分析先导发展法,包括雷击输电线路物理过程、先导发展模型参数选择、数值方法实现及模型验证,该方法能够全面模拟雷击发展的物理过程;最后,采用先导发展法分析影响线路绕击特性的因素,并讨论不同绕击分析方法的适用范围,对于500 kV及以上的超特高压线路以及同塔多回输电线路,宜采用先导发展法分析雷电绕击。该研究可为输电线路防雷设计及运行事故分析提供关键技术支撑。

基于杆塔点云数据的数字化输电线路防雷性能评估技术

针对气象条件、线路长度等因素对防雷性能产生影响,导致防雷性能评估准确度下降的问题,提出基于杆塔点云数据的数字化输电线路防雷性能评估技术。利用机载三维激光扫描技术获取杆塔点云数据,实施去噪和精简处理,提取杆塔特征参数和地形地貌特征参数,结合其他特征构成雷击风险评估指标体系。计算雷击跳闸概率值,明确雷击跳闸风险;计算输电线路的防雷程度值,确定对应的防雷等级。实验结果表明,所提方法的防雷性能评估结果与历史数据初步判定的防雷性能结果一致,该技术可以显著提高输电线路防雷性能评估的精度。

考虑暂态过电压特性的架空输电线路雷击故障时空预警方法

针对运行环境复杂多变,故障率持续居高不下,雷击故障占比较大,并具有随机性与无法预知性的问题,提出考虑暂态过电压特性的架空输电线路雷击故障时空预警方法。深入解析雷击机理与雷电流,确定雷击(感应雷与直击雷)输电线路暂态过电压计算方式,通过小波多分辨率分解算法处理输电线路暂态信号,评估暂态过电压在信号频段中的能量比,识别累计故障,判断雷击点与故障点是否一致,利用单端检测确定雷击点的位置,完成架空输电线路雷击故障的时空预警。实验数据显示,在不同实验组别背景下,当阈值pΔ取值为9.3时,雷击故障识别精度达到最大值92%,雷击点定位精度高达80%。可以获得精准的雷击故障识别结果与雷击点定位结果,充分证实了提出方法具备较好的雷击故障时空预警效果。

镇宁地区110kV架空线路雷击跳闸分析及防雷策略研究

为降低雷击对山地新能源场站电力送出的影响,提升输电线路雷害防护的有效性,本文以贵州镇宁地区某100MW光伏电站为例,首先分析场站所在区域的地理气候条件和雷电时空分布规律,通过对雷击故障的暂态波过程及杆塔雷电压、雷电流成因的探讨,深入剖析输电线路杆塔雷击放电机理。事故现场勘察结果显示,输电线路雷击跳闸主要由杆塔接地电阻超标引发的反击雷过电压,以及超出耐雷水平的直击或绕击雷过电压导致。计及雷击跳闸的主要诱导因素,本文实施若干防雷措施,包括杆塔柔性接地降阻、增强线路绝缘匹配、易击段加装无间隙氧化锌避雷器等。经实地测试,杆塔工频接地电阻显著降低且保持性较好,以全年为时间尺度,改造后线路的跳闸率远低于同区域相邻线路及本线路历史同期水平。本文研究表明,综合防雷策略能有效提升输电线路的安全性和可靠性,对雷击高发区的输电线路性能提升具有实际参考价值。

基于ATP⁃EMTP的盐铁110 kV输电线耐雷性能分析

随着输电线路的大规模建设,在电网密集区域搭建同塔双回甚至多回的线路已成为一种趋势。在雷雨多发季节,同塔双回线路遭受雷击的概率显著增加,因此针对现有同塔双回线路进行耐雷性能分析并进行相应改造显得尤为迫切。针对广西北海市盐铁110 kV同塔双回输电线进行基于电磁暂态计算程序(ATP⁃EMTP)的耐雷性能仿真,分析了多种因素对于线路耐雷水平的影响,并提出了相应的改进措施,这将有效提高盐铁110 kV线路的耐雷水平。

架空输电线路防腐蚀技术的研究进展

概述了架空输电线路的导线和绝缘子的腐蚀原因及腐蚀现状;介绍了现阶段架空输电线路的腐蚀检测技术和防腐蚀技术,重点介绍了超疏水涂层/结构和化学防腐蚀涂层的性能、原理和应用现状。

500 kV交流架空输电线路雷电性能及防护措施

[目的]雷击是造成500 kV交流输电线路故障和停电事故的主要原因,开展输电线路防雷评估对于系统的稳定运行有着极为重要的意义。[方法]依托我国某在建500 kV交流输电线路工程,根据线路基本参数等信息,通过电磁暂态程序(Electro-Magnetic Transient Program,EMTP)和改进的电气几何模型法(Electro-Geometric Model,EGM),对线路的绕击、反击耐雷性能进行了仿真研究,计算了线路的雷击跳闸(闪络)率,按照线路雷击风险划分原则确定线路杆塔的雷击风险等级,结合邻近已投运线路的实际运行数据,针对雷击风险较高的杆塔提出了雷击防护措施,并通过计算进一步验证了措施的有效性。[结果]仿真结果表明,安装线路避雷器是有效的雷击防护措施,它们可大幅降低杆塔的雷击跳闸率,提升线路耐雷性能。在采取雷击防护措施后,全线无雷击风险等级为IV级的杆塔,全线平均雷击跳闸率下降至I级的安全水平,满足《架空输电线路防雷技术导则》(Q/CSG 1107002—2018)要求。[结论]文章所提的雷击风险评估方法和防雷措施选择流程是正确并有效的,对500 kV交流架空输电线路防雷设计具有一定的工程应用价值与参考意义。

输电线路绝缘配合设计方法研究

输电线路的绝缘性能直接影响区域供电水平,且与输电线路与设备的故障发生率存在密切联系。输电线路绝缘配合设计是重要环节,也是影响输电线路运行稳定性的关键因素,设计人员应提高对绝缘配合设计方法的重视程度。主要总结了输电线路绝缘设计的基本原则与常用方法,明确了绝缘配合设计流程与设计要点,旨在提升绝缘配合设计的科学性、可靠性,进而提升输电线路与输电设备的防雷水平,降低线路跳闸等故障的发生概率,为电力行业的长远可持续发展奠定良好基础。

高压输配电线路的防雷措施探讨

我国很多高压输配电线路建设在地广人稀的区域,极易受到雷电的影响,进而导致电路跳闸的情况频发,严重影响人们的生产生活。对此,首先,对高压输配电线路雷击的危害进行介绍;其次,对高压输配电线路防雷技术进行分析;最后,结合实例,重点对高压输配电线路的防雷措施展开详细研究,并制订相关解决方案,以保证输配电线路的正常运行。

中波广播发射天馈线系统的防雷设计

中波广播发射天馈线系统工作环境复杂,防雷设计任务艰巨。分析影响天馈线防雷效果的关键因素,从器件选型、接地优化、线路防护等方面提出防雷策略。器件选择方面,在重点部位布置避雷针、隔离开关等。接地系统选用优质材料,采用多点接地以降低接地电阻。同时加强线路本身防护,提高绝缘与防水性能。这些措施可以有效保护天馈线安全。

葛泉矿风井10 kV架空线路防雷仿真研究

针对煤矿风井10 kV架空线路易受雷击,对安全用电造成威胁的问题,本文以葛泉煤矿为例,根据该矿10 kV风井架空线路防雷研究情况,对该线路进行现场及理论相关分析,通过使用PSCAD软件对线路模拟仿真,进行防雷探究。研究表明,加强线路绝缘、安设避雷器和避雷线都能够有效提高线路耐雷水平。最后结合葛泉煤矿实际情况,选用XP-70型悬式绝缘子+安设避雷线的方式,保证了雷雨季节该矿架空线路的供电可靠性,为矿井安全生产提供了保障。

超高压输电线路防雷技术的研究

为全面优化超高压输电线路安全控制水平,要结合实际应用运行环境,落实规范化防雷技术手段,搭建完整且可控的技术管理模式,维持超高压输电线路安全作业,更好地避免雷电造成的安全隐患。文章简要分析了超高压输电线路防雷技术应用的重点,并对具体的技术措施展开讨论。

架空输电线路防雷与接地的设计

随着用电需求的增大,电网工程的建设规模也逐渐扩大,架空输电线路更是呈现出大跨度的建设特点。输电线路作为电力系统的重要组成部分,一旦暴发安全隐患便会直接影响供电质量与供电安全,因此,相关人员对架空输电线路工作给予了较大的关注。雷击因素是输电线路运行中不可避免的影响因素,很大程度上威胁了供电安全。从应用和发展的层面来看,雷击问题已经成为限制电力事业健康发展的关键性问题之一。因此,对架空输电线路防雷与接地的设计要点进行梳理,以期提高输电线路的防雷接地水平,并以具体的输电线路工程为例,系统研究防雷接地设计方法。

110 kV架空输电线路防雷设计研究

为降低雷电对110 kV架空输电线路造成的影响,文章将110 kV架空输电线路作为研究切入点,结合架空输电线路的特点探讨架空输电线路防雷设计方法。研究结果表明,在110 kV架空输电线路防雷设计工作中,设计人员在做好勘察和测量工作的同时,合理设置避雷线及选择输电线路路径,结合架空输电线路的实际情况设计合理的防雷体系等,可提高110 kV架空输电线路的防雷能力,保障电力系统运行的安全性。