Prospective method of lightning protection schemes in distribution system

Grounding wires and enclosed ZnO elements have been incorporated generally in 6.6‐kV distribution systems by TEPCO for the reduction of lightning overvoltages. At present, the reliability to lightning surges is tolerably good. However, the facility of grounding wires is not inexpensive and its maintenance is hard due to corrosion and disconnection in some areas. A typical model simulating TEPCO field adopting enclosed ZnO elements has been developed and we have evaluated relative failure risks systematically according to conditions with and without grounding wires against lightning overvoltages. Two kinds of failures discussed in the paper are the flashover of insulation and the overduty of ZnO elements, and two kinds of induced and direct lightning overvoltages are studied in flashover. The greatest problem with no grounding wire is the increase of ZnO elements' duty, but it was demonstrated that a short partial grounding wire around ZnO elements or the selection of heavier ZnO elements provides a solution. The main objectives of this study are to clarify the relative failure risks systematically according to realistic field conditions, the risk of small stroke currents having long duration to ZnO elements' duty, and countermeasures against ZnO elements' overduty. © 1999 Scripta Technica, Electr Eng Jpn, 127(1): 1–10, 1999     

10kV配电线路综合防雷保护研究

为研究低幅值雷电流和感应雷导致配电线路绝缘发生的闪络,以浙江省诸暨地区某10 kV配电线路为例,分析配电线路雷击跳闸率居高不下的原因和配电线路雷电过电压的产生机理,并通过场线耦合模型,运用数值计算的方法对配电线路的雷电感应过电压进行了计算,最后结合配电线路的实际运行情况,提出了配电线路的综合防雷措施。     

海南强雷区典型配电线路差异化防雷措施研究

海南地处我国最南端,雷电活动极为强烈,绝缘水平较低的10kV配电线路极易因雷击跳闸,直接影响海南工农业生产生活用电.因此,有效提高10kV配电线路防雷性能评估水平与治理能力,对保证海南地区供电的稳定可靠十分重要.本文采用配电网差异化防雷技术开展海南强雷区10kV配电线路防雷综合治理研究,首先建立综合考虑雷电信息、线路结...     

同塔双回线路防雷综述

随着同塔双回线路的大量投运,预防雷跳闸对稳定运行愈显重要,对国内外同塔双回线路运用较多的国家及省份在同塔双回线路防雷措施的应用进行了调查和分析,提出了影响同塔双回线路雷击跳闸的因素和防雷建议.     

A distribution line model for lightning overvoltage studies

Recently, the focus of lightning protection measures for distribution lines has moved from a nearby lightning stroke to a direct lightning stroke. Studies of direct lightning stroke countermeasures are generally carried out by digital simulations using the EMTP (Electro‐Magnetic Transients Program). Thus, components of a distribution line must be modeled appropriately in the EMTP for accurate simulations. The authors have previously clarified the surge response of a distribution line by pulse tests using a reduced‐scale distribution line model. In this paper, first, the results of the pulse tests are simulated in the EMTP using a conventional model which represents a distribution pole by a single lossless distributed‐parameter line model, and comparisons with the test results show that transient overvoltages generated at the insulators cannot accurately be reproduced by the conventional model. This indicates that a special treatment is required to represent the transient response of a distribution pole and wires. Then, this paper proposes new EMTP models of the pole and wires which can reproduce the transient overvoltages at the insulators. The parameter values of the proposed models can be determined based on a pulse test result. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 173(1): 11–23, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.21001     

特高压线路的避雷线保护范围设计

目前,在特高压线路的避雷线保护范围设计中,仍采用传统的不考虑特高压导线电压影响的方法,可能使特高压线路避雷线的实际保护范围满足不了高可靠性防雷设计的要求。为了解决这一问题,在特高压线路的避雷线保护范围设计中,考虑特高压导线电压的影响,提出以特高压导线的最小对地空气间隙距离为半径,构成特高压导线的等效绝缘截面,并设计该等效绝缘截面位于避雷线的保护范围之内。计算结果表明,若不考虑特高压导线电压的影响,特高压线路的避雷线保护范围将存在严重的安全隐患。     

配电线路感应雷过电压计算

为研究雷电感应过电压特性,提出了一种基于MODELS语言并应用ATP-EMTP软件计算多导体传输线感应过电压的新方法.计算时考虑了大地损耗对垂直电场的影响,并且在计算过程中将线路本身等效为无损传输线.将实际计算的结果与火箭引雷实测数值以及其他模型计算结果进行了对比,验证了该方法的有效性。     

农村配电网线路和设备的防雷接地保护研究

针对1起10 kV配电变压器高压侧避雷器爆炸引起的低压侧用户电击死亡事件,分析农村配电网的防雷保护和低压配电线路上用户的电气安装等问题,并提出相应的修改措施。     

输电线路雷害分析及防雷措施

基于对黄冈电网220kV及以上输电线路历年雷击闪络故障的分析,以及找到的故障原因,提出了降低杆塔接地电阻、加装线路避雷器和安装可控放电避雷针等多种防雷措施,并进行了实施,经过实际运行验证,采取的这些防雷措施有效地降低了线路雷击跳闸率。     

输电线路防雷措施探讨

根据我局2009年至2010年110kV及以上输电线路跳闸情况分析,雷击跳闸占线路事故掉闸次数的52．6％,110kV线路雷击跳闸占46．67％,220kV线路雷击跳闸占事故掉闸次数的75％,因此,2011年提高输电线路运行可靠性的技术方案主要围绕防雷开展,线路防雷主要是改造接地体和安装避雷器、综合防雷装置以及可控避雷针等。     

贵州山区110kV及以上输电线路防雷运行

对2007-2009年贵州山区雷暴日、地面落雷密度等雷电参数以及110～500kV输电线路雷击跳闸情况进行统计分析,指出贵州山区雷电活动活跃以及地表以岩石为主是贵州电网输电线路雷击跳闸率高的主要原因,并提出防雷工作存在的问题以及下阶段防雷工作建议。     

10kV配电线路的防雷技术

阐述了雷电对配电线路造成的危害,介绍了舞阳地区10 kV配电线路发生的雷害故障情况,分析了舞阳地区配电网在防雷措施和防雷设备上存在的问题,并对这些问题提出了相应的解决措施。     

对我国500kV线路防雷的新思考

雷电定向定位仪测量的雷击跳闸时的雷电流幅值分布为500kV线路防雷提供了宝贵的运行经验,它表明绕击是造成500kV线路雷击跳闸的主要原因,而不是传统观念中的反击。而地面倾斜角对绕击率又有较大的影响。在研究防雷措施时要适当地修正思维方式,要特别重视防止绕击跳闸。我国现有规程推荐的雷击跳闸率计算方法存在有待改进的地方。     

林水-郁南110kV输电线路的防雷研究

在雷害特别严重地区，输电线路的雷电击杆率高，雷电流幅值大，线路防雷的重点应是降低杆塔的雷电击杆率，分流并限制雷电流，以减弱雷电流的强度。     

Series compensated line protection enhancement by modified pilot relaying schemes

In this paper, a comprehensive analysis of the impact of series capacitor on the performance of communication-aided distance protection schemes of transmission lines is presented. It is shown that not only the series capacitor and its overvoltage protection affect the distance protection of its line, but also the adjacent lines would experience protection problems. Mitigation of this problem is proposed by using new communication-aided schemes. The proposed schemes use the information available at the substation to inhibit relay malfunctions. The performance of the techniques is studied for different series capacitor locations in the transmission line. Real Time Digital Simulator (RTDS) and four sophisticated commercial relays are used for testing. The results verify the impact of series capacitor on the conventional communication-aided schemes and also the effectiveness of the proposed methods     

Computer aided coordination of line protection schemes: IEEEcommittee report

The IEEE PSRC Working Group on Computer Aided Coordination of Line Protection Schemes was established in 1985 to investigate the application of computers to the task of setting and verifying the setting of line protective devices. This report provides the findings of the Working Group regarding the functional requirements of the database, software, and hardware for this system as well as the methods of presenting the results to the protection engineer     

35kV架空线路的防雷技术措施研究

本文说明了如何选择合理的线路路径,合理设计杆塔与避雷线截面。主要介绍35kV线路采用自动重合闸装置及不平衡方式加装绝缘子来提高线路的耐雷水平。     

通信防雷的技术措施

通信系统的防雷设计和电磁干扰防护是保护通信线路、设备及人身安全的重要手段,也是通信网正常运行不可缺少的技术环节.文章首先说明了雷击对通信设备产生的危害,强调了防雷的重要性,并从通信设备和环境防雷入手,重点阐述了防雷的主要技术措施.     

1 000 kV特高压交流试验示范工程线路走廊雷电分布特征研究

为给特高压交流试验示范工程防雷设计及今后运行提供参考依据,利用覆盖输电线路的中国电网雷电监测网2002—2005年185万次地闪主放电监测数据,采用网格法将线路走廊以0.2°×0.2°(约20km×20km)等间隔划分网格,从北向南依次编号为0￣28,对这29个"统计段"的雷电日Td、地闪密度Ng、地面落雷密度g、雷电流幅值概率分布P(I)进行统计分析,得出沿线路走廊雷电活动分布特征,同时分析认为晋东南段(0￣3)的危险雷电流所占比例和地闪密度均最集中,是特高压线路中容易遭受雷击并发生闪络的薄弱线段,在防雷设计和今后运行中应引起足够重视。     

变电站直击雷保护分析

为了防止雷电灾害,保证电力系统安全稳定运行,阐述了变电站的直击雷保护措施和保护作用原理,提出了防雷措施,用折线法对单避雷针(线)保护范围及双避雷针(线)构成的联合保护进行了分析。分析结果表明,变电所内的所有设备及建筑物在避雷针(线)的保护范围之内能够避免遭受直击雷的威胁,同时应将接地装置的接地电阻降低到规程允许值,保证避雷针(线)与临近的配电装置及建筑物的安全距离。