架空线路防绕击避雷针实用化技术

为了探讨输电线路防雷新技术、新方法,降低雷击电跳闸率,结合国内外输电线路及特高压的运行经验,着重分析了引起高压输电线路故障跳闸的主要原因—雷电绕击问题,并在输电线路防雷经典理论的基础上,利用电气几何模型和雷电先导理论的最新成果,研究了架空线路防绕击避雷针实用化技术。研究表明,在架空地线上合理装设防绕击避雷针,可有效地增强其屏蔽性能和引雷作用,将可能遭受的绕击控制转化为反击,大幅度降低雷击故障跳闸率。实际运行的情况和初步取得的效果为输电线路防雷治理及特高压电网建设积累了经验。     

1000kV交流输电工程防雷保护研究

为解决特高压工程中的外绝缘问题,研究了特高压线路雷电性能和特高压变电所和开关站雷电侵入波过电压。研究线路雷电性能时考虑了单回和同塔双回线路。比较了不同塔型线路的雷电性能后指出,造成特高压线路雷击跳闸的主要原因是绕击,要特别重视地面倾斜角较大的山区线路的绕击问题。建议减小地线保护角和地导线的垂直距离Δh以减小绕击跳闸率。最后计算分析了晋东南GIS变电所和荆门HGIS变电所站的雷电侵入波并根据两个变电所各自的特点提出相应的MOA布置方案及其防雷可靠性分析。     

1000kV特高压交流输电线路防雷电绕击技术

雷电绕击是造成特高压输电线路跳闸的主要原因.根据国内外输电线路现有防雷技术及运行经验,综合分析几种防雷电绕击实用新技术,并且探讨各防雷技术用于特高压交流输电线路的可行性及适用范围,以期为我国1 000kV特高压交流输电线路防雷电绕击提供支持.     

浅析1000kV特高压输电线路防雷

特高压输电线路防雷,是保证特高压输电线路安全运行的重要环节之一。介绍并分析了利用规程法和电气几何模型法对1 000 kV特高压输电线路绕击、反击以及雷电直击中线进行雷击计算的结果,并据此提出了减小1 000 kV特高压输电线路雷击跳闸率的具体措施。     

三条110 kV山区输电线路防雷装置运行情况分析

通过分析三条１１０ＫＶ山区输电线路防雷装置的运行情况,指出输电线路防雷要同时采用多种防雷措施降低雷电跳闸率,而降低杆塔的接地电阻,提高线路的耐雷水平是降低山区输电线路雷电跳闸率的一个基本手段。     

交流特高压线路绕击防护性能研究

为将我国特高压线路雷击跳闸率控制在允许范围,分析了前苏联和日本特高压线路防雷的经验和教训,对各种特高压杆塔方案的雷电性能进行研究,重点讨论了各种双回线路杆塔的绕击特性。分析表明,前苏联特高压线路雷击跳闸率较高的原因主要是避雷线保护角较大,而日本主要是由于线路多经山区且杆塔高度较高。对我国特高压线路雷击跳闸率的计算表明,单回线路猫头塔在平原可满足雷击跳闸率要求,山区采用酒杯塔应适当降低保护角或杆塔高度。双回线路V形串伞形塔由于导线布置合理、保护角小,其绕击防护性能最佳,在地面倾角为20°的山区雷击跳闸率仍可满足要求,收腰形塔、I形串伞形塔和鼓形塔均能在平原地区满足要求,但在山区使用时则需降低保护角和杆塔高度。     

广东雷电活动规律及输电线路雷击跳闸分析

分析了2005—2012年广东雷电活动规律及雷击跳闸情况,表明各年50%概率雷电流幅值集中在26~35kA之间,雷击跳闸率受50%概率雷电流幅值的影响较地闪密度大;同塔多回输电线路雷击同时跳闸占雷击跳闸比例达15%~30%。提出了防雷策略,包括输电线路防雷需要抓住重点,转变观念,加强管理;重视常规防雷措施的基础上,重点治理易击重要线路和同塔架设线路,提高线路雷击跳闸重合成功率。     

广东输电线路防雷运行分析

统计分析2001-2007年广东地区地面落雷密度、雷电流幅值概率分布等雷电参数,线路雷击导致变电设备受损、线路雷击跳闸比例、雷击跳闸率等防雷运行参数,指出广东电网雷击跳闸率偏高的原因、存在的问题及今后防雷工作的重点,建议加强输电线路的综合防雷改造,适当提高广东线路的防雷设计标准。     

1000kV/500kV特、超高压同塔4回交流输电线路雷电性能仿真分析

为准确评估1 000kV/500kV超特高压同塔4回输电线路的雷电性能,基于电磁暂态程序(EMTP)和改进后的电气几何模型(EGM)分别对这种线路的反击、绕击耐雷水平及雷电跳闸率进行了仿真研究。分析了同塔多回线路中500kV线路不同相序排列、不同间隙长度及不同杆塔冲击接地电阻对反击跳闸率的影响,并对比计算了1 000kV线路不同绝缘子串布置方式下线路的雷电绕击性能。最后根据研究结果,指出了500kV线路的绝缘配合是1 000kV/500kV混压同塔4回线路防雷的薄弱点所在,并提出通过加强500kV线路的绝缘水平、优化1 000kV线路绝缘子的布置方式等措施,能有效改善线路雷电性能、降低雷击跳闸率,可用于指导工程设计。     

输电线路差异化防雷评估

新疆地形地貌呈现多样性,全区部分地区夏季雷电活动较频繁。随着新疆特高压建设工程的不断推进,电网的雷电监测与防护要求也日益提高。输电线路差异化防雷将影响线路耐雷水平的雷电信息、地形地貌参数及线路基本信息多方面自然影响因子科学融合,形成可准确筛选潜在高风险杆塔并制定高经济性改造方案的线路雷害防御技术。着重以雷电参数统计建立雷击杆塔跳闸率模型,通过指标判断杆塔防雷性能。采用先评估、后治理、再总结的方式,对输电线路进行可靠性评估。     

宜昌地区高压输电线路防雷运行分析

介绍了宜昌地区近１５年来１１０ＫＶ及２２０ＫＶ输电线路运行所积累的防雷运行经验,对影响高压输电线路雷电跳闸率的各种因素进行了分析,并提出改进高压线路防雷措施的建议。     

500kV同塔双回输电线路雷电反击仿真模型的建立与分析

雷击是造成输电线路跳闸的主要原因。做好500kV同塔双回输电线路防雷设计,是保证电力系统安全运行的重要环节之一。以某500kV线路为研究背景,用ATP-EMTP软件分别建立雷电流双指数波模型、杆塔分段传输线模型、输电线路Jmarti模型、绝缘子闪络和冲击接地电阻模型,搭建仿真电路,分析了接地电阻和线路档距对500kV同塔双回线路的反击耐雷水平的影响,以期为我国500kV同塔双回线路防雷分析提供参考。     

多导体配电线路感应雷过电压分析

为分析多导体架空线负载感应雷过电压及架空地线屏蔽特性,利用傅里叶变换计算雷电流的频谱分布,根据求多导体传输线负载响应的BLT方程,在频域内求其外电磁场激励下的电报方程,计算多导体配电线路感应雷过电压的频域响应,再根据傅里叶反变换求得负载端的暂态响应。配电线路感应雷过电压特性及架空地线屏蔽作用的分析结果表明,线路垂直排列时,感应雷在负载端引起的差模干扰较大,大地电导率越小架空地线的屏蔽作用越好。     

2000～2007年输电线路雷击闪络统计分析(英文)

Lightning stroke is one of the important causes of the accidents that occur on transmission lines. With the development of power system, the proportion of outages on transmission lines because of lightning stroke also increases. And according to the lightning accidents results, the lightning stroke characteristics is related to the time factors tightly. In order to analyze the correlativity between the lightning flashover amount and the time factors, about 425 times lightning flashover on 187 lines in 10 power supply companies of 220 kV and 500 kV transmission lines during 2000～2007 are investigated in this paper. The correlativity between the lightning flashover amount and the time factors is analyzed. According to the lightning stroke accidents investigation records, the lightning flashover amount of transmission line increases from the year of 2000 to 2007. In each year lightning flashovers mostly happen in the month of June, July and August. Similarly in each day the flashover amount also varies with the time of day obviously. These lightning flashovers mainly occur during 14:00～21:00 in the afternoon. The analysis results in this paper have a good agreement with the meteorological observations and lightning detection data of lightning location system (LLS). And these results provide good reference for the lightning protection work in power system.     

Reducing the effects of lightning in cogeneration plants

Georgia Transmission Corporation (GTC) serves the Weyerbaeuser Flint River Mill in Oglethorpe, GA, with a new, nondedicated 115 kV radial-transmission line connecting from the North Americus substation with a tap to the South Oglethorpe substation. The Flint River mill is a cogenerator with a single 46.6 MVA steam-turbine generator fueled by biomass. The line suffered from repeated outages, primarily due to lightning strikes, since the day it was commissioned. As a result, increased attention and concern has been given to the problems associated with resultant voltage fluctuations and momentary outages in the mill. More effort has been placed on service reliability and tracking these fluctuations and outages. Several lightning engineering programs have been studied. In particular, the Windows-based Lightning-Protection Design Workstation, developed by EPRI, was investigated. The program was used to provide a comparison of pole-line configuration, arrester usage, and static protection as would relate to power outages. It calculates the lightning performances of overhead transmission lines and indicates what, if any, flashover design improvements are required to reduce iightning-caused outages. A further investigation involved the use of a computer-based scope with the ability to see storms over 483 km (300 mi) away. Early detection of storms with the potential to produce strikes on the mill site or the transmission line will allow the mill to take the necessary steps to operate independently from the electric utility company until the thunderstorm subsides     

Analysis of the Mexican lightning activity monitored by NASA satellites

Lightning is the main cause of transmission line outages in Mexico. For this reason, it is necessary to investigate the areas where lightning occurs more frequently in order to improve or establish necessary countermeasures.Since 1998, the Mexican Institute for Electrical Research has been gathering the database recorded by the operational line scan (OLS), optical transient detector (OTD) and lightning imaging sensor (LIS) systems from USA-NASA. These systems have been installed in satellites to detect and count lightning occurring all around the world.This information has been analyzed by the IIE to perform seasonal maps of atmospheric discharge frequency along the Mexican Republic. The obtained maps have shown a good agreement with the statistic of transmission line outages caused by lightning. Namely, the zones determined with the highest discharges frequency are those where the highest number of line outages have been reported by the Mexican electrical utility Comision Federal de Electricidad (CFE).     

Lightning and surge protection of substations

Lightning and switching transients along with ground faults create significant voltage anomalies on transmission and some distribution circuits. Not only direct strikes, but nearby strikes, create significant voltage anomalies and subsequent line outages. Developments have made it possible to provide a solution to lightning and surge problems, and also reduce the overall cost of substation designs. It is now possible to prevent lightning strikes to any substation component (including the protection system), and to limit incoming transient voltages to as little as 10% over their normal sine wave peaks. This paper defines the problem confronting protection systems engineers, reviews the protection systems conventionally used and defines two new protective systems: the Dissipation Array System (DAS) and the series hybrid forms of surge protection. The DAS has been in use for over twenty years as a strike preventer. The series hybrid protection concept is new to substation applications, but has been in use at secondary levels of up to 2500 V for approximately sixteen years. As a result, lightning or other forms of transient phenomena does not need to be a threat to substations or drive up the overall costs     

Effective lightning protection schemes for distribution line

The causes of lightning outage are subdivided into direct lightning strokes and induced lightning strokes, which are identified by the characteristics of the lightning overvoltage. In the past, lightning protection devices were directed mainly toward the latter, and attention has been focused on the installation of lightning protection devices, ground wires, and reinforcement of insulators. However, lightning outages continue to occur. Thus it is extremely important to clarify the fault characteristics of lightning surges and to study the effectiveness of various lightning protection devices by considering both direct lightning stroke and induced lightning stroke in order to prevent lightning outage in the future. In this research, the electromagnetic transients program (EMTP) has been applied to the direct lightning stroke, and the induced lightning outage analysis program for multiple conductor systems has been applied to the induced lightning stroke to study the effectiveness of lightning protection devices provided by combination of various lightning protection devices. The most effective lightning protection schemes are analyzed and evaluated based on verification tests on the full scale models as well as economic considerations.     

Lightning protection of overhead power distribution lines

There are two major protective methods against lightning outages on overhead distribution lines. One is by use of surge arresters and the other is by an overhead ground wire. Surge arresters have rather constant effect regardless of the type of lightning outage causes. On the other hand, the effect of an overhead ground wire is quite different against the two major causes: direct lightning hit and induced overvoltages. This paper shows how to design lightning protection for overhead power distribution lines taking these characteristics into account. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.