Estimation of the surge arrester outage rate caused by lightning overvoltages

The computation based on the lightning limiting parameters method of the surge arrester minimum energy absorption capability is presented. The sensitivity analyses of certain lightning parameters like lightning current-wave duration and equivalent circuit parameters are performed. The influence of the tower footing impedance to the surge arrester failure rate due to the exceeding energy absorption capability is investigated. The method of selection of the medium voltage surge arrester energy absorption capability based on the allowed failure rate is proposed.     

Assessment of surge arrester failure rate and application studies in Hellenic high voltage transmission lines

The use of transmission line surge arresters to improve the lightning performance of transmission lines is becoming more common. Especially in areas with high soil resistivity and ground flash density, surge arresters constitute the most effective protection mean. In this paper a methodology for assessing the surge arrester failure rate based on the electrogeometrical model is presented. Critical currents that exceed arresters rated energy stress were estimated by the use of a simulation tool. The methodology is applied on operating Hellenic transmission lines of 150 kV. Several case studies are analyzed by installing surge arresters on different intervals, in relation to the region's tower footing resistance and the ground flash density. The obtained results are compared with real records of outage rate showing the effectiveness of the surge arresters in the reduction of the recorded failure rate. The presented methodology can be proved valuable to the studies of electric power systems designers intending in a more effective lightning protection, reducing the operational costs and providing continuity of service.     

合理布置线路避雷器，降低跳闸率

本文分析了 2 2 0 k V韶郭线安装线路避雷器后耐雷水平的变化 ,肯定了使用避雷器后取得的防雷效果 ,并简述了耐雷水平的计算和技术经济比较。     

110kV线路避雷器受潮分析

通过介绍110kV变电站110kV线路避雷器内部受潮发热的情况,对故障情况进行试验分析,找出了避雷器受潮发热的原因是密封胶老化龟裂,潮气进入避雷器本体,引起受潮发热,并提出了相应的预防措施,防止类似问题的再次发生。     

Maintenance of surge arrester by a portable arrester leakagecurrent detector

An instrument is described that detects leakage current without disconnecting the arrester ground wire. Better means were developed for detecting deterioration of a surge arrester than the existing appearance inspection, insulation resistance measurement, and leakage current measurement. The device measures only the in component of the current, which is proportional to the power loss. The change of the latter is the recognized measure of deterioration     

发电机雷电过电压的在线分析研究

介绍了雷电冲击时发电机绕组的电压分布情况 ,给出了一种在线测量雷电波形和计算发电机绕组电压的方法 ,建立了相应的数学模型。同时 ,通过在雷击瞬间测量发电机出线端过电压 ,对穿过绕组的雷电过电压进行了计算机仿真     

Impact of surge arrester number and placement on reliability and lightning overvoltage level in high voltage substations

Surge arresters are the most critical equipment for protecting high voltage substations. They play an important role in substations for limiting switching and lightning surges and diverting these surges to ground. On the other hand, surge arrester number and placement for high voltage substations can be determined based on some evaluations in the designing process of substations. Surge arresters can be placed on the both ends of substations, transformers, circuit breakers, reactors, capacitors and also high long bus-bars and etc. Therefore, failure of arresters during overvoltage can put substations in risk condition. Moreover, surge arresters may be inclined to be short circuit during normal operation condition due to ageing process and/or improper quality. This paper attempts to assess reliability of three common substation configurations namely: (1) one breaker and a half; (2) double-bus double-breaker; and (3) ring bus-bar in different placement of surge arresters. At first, maximum voltages on equipment are calculated in different lightning stroke locations through simulation in EMTP-RV. Studies without surge arrester and the presence of surge arrester in different locations are analyzed and compared. Then surge arrester’s placement impacts on the substations reliability indices are calculated in normal operating condition and overvoltage condition by minimal cut set method and simulation results. Analytical studies reveal that surge arrester can increase substations reliability. But for low annual number of lightning stroke, substation reliability may decrease. Also increasing surge arrester number more than substation need reduces reliability.     

Evaluation of lightning fault rate of EHV transmission line based on lightning parameters derived from electromagnetic observation

Cloud-to-ground lightning flashes in the Niigata area in Japan have been observed for a few years by a magnetic direction-finder network. Data obtained so far are analyzed carefully taking into account the operating characteristics of the system. As a result, frequency distributions of return-stroke current for each polarity are produced, and their seasonal variations and the occurrence probabilities of high current exceeding 200 kA are clarified. Based on the estimated current distributions, back-flashover rates of 500-kV 2 cct transmission lines are calculated. It is known that the back-flashover caused by downward flashes can account for most of the line outages in the summer for both single- and multiple-line faults. However, this mechanism cannot explain the high outage rate in the winter experienced in the winter thunderstorm area in the late 1970s. In spite of the low lightning flash density in the winter, the multiple-line fault rate in the winter caused by back-flashovers is predicted to be comparable to that in the summer, because of the seasonal variation of the frequency distributions of return-stroke current.     

避雷器研究新课题

现代避雷器经历两次“革命”后，在主体性能、结构方面已基本无发展空间。避雷器的研究应侧重于高梯度电阻片、老化密封、机械耐受、压力释放等重要性能的改善，并拓宽其使用场合。     

A parameter identification technique for metal-oxide surge arrester models

A simple numerical technique to identify the parameters of metal-oxide arrester models is described. Using measured arrester voltage obtained under impulse test conditions the arrester parameters are determined using an optimization technique. The validity and the accuracy of the model are then assessed by comparing the predicted against the measured values of arrester energy, initial slope, residual voltage, and the overall deviation. Application of the arrester model on network system studies is illustrated.     

应用线路避雷器提高10 kV配电线路防雷性能的研究

配电网系统作为电力系统的重要组成部分,承担着直接向用户供电的任务,是连接电网和用户的纽带,其安全运行非常重要.10 kV配电线路由于绝缘水平低的特点,易发生雷击过电压而造成绝缘事故.因此,10 kV配电线路的防雷保护是保证配电网安全运行、提高供电可靠性的重要措施.结合广东高要配电网的工程实际,以10 kV大企线为例,计算配电线路的耐雷水平和雷击跳闸率,并建立相应的ATP仿真模型,通过对安装线路避雷器前后的线路过电压水平的仿真计算,验证其能够有效提高配电线路的防雷性能,为工程设计提供有价值的基本数据.     

应用线路避雷器提高10 kV配电线路防雷性能的研究

配电网系统作为电力系统的重要组成部分,承担着直接向用户供电的任务,是连接电网和用户的纽带,其安全运行非常重要。10 kV配电线路由于绝缘水平低的特点,易发生雷击过电压而造成绝缘事故。因此,10 kV配电线路的防雷保护是保证配电网安全运行、提高供电可靠性的重要措施。结合广东高要配电网的工程实际,以10 kV大企线为例,计算配电线路的耐雷水平和雷击跳闸率,并建立相应的ATP仿真模型,通过对安装线路避雷器前后的线路过电压水平的仿真计算,验证其能够有效提高配电线路的防雷性能,为工程设计提供有价值的基本数据。     

避雷器计数器综合校验装置

介绍了一种新型便携式避雷器计数器综合校验装置及其各功能实现,阐述了设计思路及方法,使避雷器计数器和监测器现场检测工具小型化和智能化。     

2006年绝缘子避雷器行业经济运行分析

伴随着国家"十五"计划的完成及"十一五"计划的启动实施,我国电网建设将以大容量、长距离、大跨越、特高压为特点进入一个新的发展阶段,绝缘子避雷器行业是输配电设备的重要组成部分,发电装机容量的增长速度是本行业需求量预测的重要依据.     

信号避雷器在电力通信系统中的应用

为了防止雷电通过直击雷过电压和感应过电压这2种途径入侵电力通信系统,提出采用通信弱电信号电涌保护器(SPD)的防范措施。但运用SPD防雷的同时,也会给线路的正常传输带来诸如产生插入损耗等负面影响。为了消除不利因素,文章分析了产生插入损耗的原因,讨论了SPD的主要技术参数和运用原则,介绍了选择、安装、维护SPD的注意事项,以便读者了解和掌握SPD的正确使用方法,在实践中将其负面影响降至最低。     

Modeling metal oxide surge arrester for the modern polarization based diagnostics

Recently a number of new non-destructive diagnostic techniques have been investigated for the reliable condition assessment of the ageing of metal oxide surge arrester (MOSA). Among them polarization/depolarization current and return voltage measurement techniques showed very promising results. This paper presents an insulation polarization model for investigating polarization-based diagnostics for metal oxide surge arrester. The simulations of the proposed model are validated and verified by comparing the data from the polarization/depolarization current measurements. The simulation of return voltage for MOSA is also performed to validate the insulation polarization model. Finally, the usefulness of this model for MOSA diagnostics has been highlighted in this paper.     

避雷器监测系统关键技术实现方案研究

针对变电站运行维护人员在使用避雷器监测系统中所存在的实际技术问题,在介绍了新型避雷器监测系统整体实现方案之后,对于采集单元准确获取同步命令的关键技术进行了研究。通过分析综合流水线滤波法和步长滤波法,提出了全新的数字滤波法,并进行了仿真与验证;通过实时获取监测系统内避雷器监测单元晶振间隔计数,实现各个避雷器采集单元的同步相位补偿,并收到了良好的效果。文章提出的实现方案在产品实物上进行了实现和验证,对于避雷器采集单元关键技术的解决有一定的参考价值。     

35kV主变压器中性点避雷器的运用

针对近年来35 kV变压器雷击损坏情况,分析了雷电波在变压器绕组中的波过程,提出抑制变压器中性点过电压的措施。通过经济和可靠性比较得出在变压器中性点加装金属氧化锌避雷器的措施,并结合运行情况证明了其有效性。     

多柱并联避雷器直流参数测量方法

针对多柱并联避雷器测量1 mA直流参考电压U_{1 mA}及0.75倍U_{1 mA}下的泄漏电流所需试验仪器容量大以及测量过程中避雷器高压端法兰间存在幅值不确定的悬浮电位问题,开展多柱并联避雷器不拆除避雷器本体试验方法研究。提出通过电阻分压法降低避雷器高压端法兰之间的压差和直流高压发生器的输出容量。通过试验从避雷器高压端法兰电位差、所需试验电流和测量准确性等三方面论证了电阻分压法测量多柱并联避雷器直流参数的可行性,为多柱并联避雷器例行试验提供了理论支撑。