Suppression of lightning-induced overvoltages by distribution line surge arresters

The primary aim of surge arresters in power distribution lines is to protect lines and equipment from the voltage induced by nearby lightning strokes. To further improve power systems, methods to protect distribution lines against direct lightning strokes are still needed. An effective measure against direct lightning strokes is to increase the number of arresters. However, if the surge current is too large, some surge arresters absorb energy in excess of their capability and may break; this leads to a line fault. To evaluate the protective effect of the surge arresters against direct lightning strokes to overhead ground wire, the authors measured both the voltage across the surge arresters and the energy absorbed by them using a full-scale model line and a 12 MV impulse generator. The results were compared with simulation results by EMTP. There have been no previous studies making a comparison of this kind.     

复合外套金属氧化物避雷器在110kV中悦线的应用效果

分析和介绍输电线路用复合外套金属氧化物避雷器（PMOA）的工作原理和功能及在110kV中悦线安装PMOA的使用效果，并提出PMOA是山区线路防雷，提高线路运行可靠性的有效措施。     

线路避雷器在广东电网输电线路上异常运行情况的分析

对广东电网应用线路避雷器作为输电线路防雷新措施实施9年以来线路避雷器所发生的异常运行情况进行了分析,包括了产品质量原因引起的故障、安装或选点不当等原因引起的运行异常以及自然灾害或极端气象条件引起的线路避雷器损坏等。总结了安装及运行经验,提出相应的对策,为线路避雷器这项新技术的推广应用提供了指导。     

Application studies of line arresters in partially shielded 138-kV transmission lines

The application of arresters on transmission lines has been one of the most effective alternatives for the reduction of lightning flashover rates. This paper reviews previous methods for evaluating lightning performance of lines with arresters. Improved calculations of line outage rates are developed to include power frequency voltage and arrester failure-rate evaluations, based on field experience. The transmission lines are modeled in detail in the electromagnetic transients program (EMTP)/(ATP) and the outage rates are calculated with the Monte Carlo method. Probability energy stresses on arresters are evaluated for strokes on conductors and shield wires as a function of tower footing resistance (TFR).     

Development of polymeric surge ZnO arresters for 500-kV compact transmission line

The 500-kV polymeric ZnO surge arresters for compact transmission line against lightning overvoltage were developed and have been put into operation, which consists of arrester unit and series gap. The design of the arrester unit, including structure design, selection of ZnO varistor, parameter determination, polymeric housing design, and mechanical structure design was discussed. The design of the series gap and the determination of the series gap length were presented. The calculated results state the line surge arrester can highly improve the lightning withstand level of the compact transmission line, and the line surge arrester can withstand the effects of lightning.     

浅议220 kV韶郭线安装氧化锌避雷器后的运行效果

韶关电厂至郭塘变电站的２２０ｋＶ输变电线路大部分杆塔地处粤北山区,雷电活动强烈,常发生雷击跳闸故障。为此,选择在韶郭线雷电易击段安装氧化锌避雷器的方法,来提高线路的防雷性能。通过雷电定位系统的分析比较,安装氧化锌避雷器后,线路跳闸次数明显下降,事实证明这种方法的防雷效果较好。     

Investigation of effect of transmission line arresters verified by lightning surges at substations

In recent years, transmission line arresters have been installed to protect overhead power transmission lines from backflashovers caused by lightning. In addition, it has been expected that substation lightning surges incoming via transmission lines can be suppressed by them. However, the suppression effect by those with series gaps has not been investigated sufficiently. The author has measured lightning surges at two 77‐kV substations from 1990 to 1993. As the transmission line arresters have been mounted on the towers since 1992, the lightning surges due to the sparkover of the series gap of the transmission line arresters can be observed at the substations. In this paper, the lightning surge waveforms due to such sparkover have been analyzed in detail. Next, an accurate EMTP simulation method considering the induced lightning surge voltages has been proposed. Finally, their suppression effect has been investigated by simulation corresponding to each mounting method. © 1999 Scripta Technica, Electr Eng Jpn, 126(4): 30–39, 1999     

Metal oxide arresters on distribution systems: fundamentalconsiderations

The authors compare the reliability of metal oxide and silicon carbide distribution arresters by examining the likelihood of failure as a result of moisture leakage and contamination, overvoltages, and lightning surges of high magnitude and long duration. It is found that metal oxide distribution arresters should be highly reliable in most applications because the arresters are far less likely than silicon carbide arresters to fail as a result of moisture ingress and contamination. Metal oxide arresters are more likely to fail as a result of system overvoltages because they conduct current in response to the overvoltages, and for this reason somewhat more care must be exercised in application to match the magnitude and time duration of system overvoltages to the temporary overvoltage capability of the arresters. Comparison of published metal oxide arrester energy absorbing capability against the energy absorbed in lightning surges that have been shown to exist indicates that the probability of failure may be high in areas of high lightning intensity. The authors suggest changes in the ANSI/IEEE C62.11 standard for metal oxide arresters to improve arrester reliability on lightning surges     

线路避雷器在线路防雷上的应用效果

为了减少雷击对输电线路的伤害,将线路避雷器安装在输电线路的易击段,可以提高线路的耐雷水平。鉴此,介绍了线路避雷器防雷的基本原理和安装前的准备工作。并对近年来肇庆四会供电分公司部分已挂网运行的避雷器进行了跟踪分析,原多雷击杆塔自从加装了线路带串联间隙避雷器后,迄今杆塔未发生雷击跳闸。     

Numerical analysis of overhead transmission line galloping considering wind turbulence

This study aims at clarifying the factors that cause transmission line galloping and the conditions influencing it, and at determining response evaluation indices of gallopings in turbulent flows. This is done using a three‐dimensional analytical method considering a large deformation. The analysis is based on four‐bundle transmission lines. Obtained results are as follows:

• 1 The occurrence of galloping in the smooth flow is limited by the combination of the following parameters: the initial angle of wind attack, the initial icing angle, and the wind speed. The galloping predominates mainly with one or two of the lowest in‐plane, out‐of‐plane, and torsional modes for the free vibration under the conditions that the transmission line is subject to dead load as well as static wind force. However, the galloping always occurs with torsional vibration.
• 2 The shape of the Lissajous figure for displacement depends on the initial angle of wind attack and the initial icing angle, as well as wind speed. The main shapes are vertically elliptic, horizontally elliptic, and a configuration having the shape of a horizontally rotated figure of eight.
• 3 The predominant frequency components of gallopings in turbulent flows are amplified and controlled by the turbulence intensity. Vibration frequency components unrelated to galloping increase linearly with rise in turbulence intensity.
• 4 There is a time lag of 30 s between galloping vibration and the fluctuating wind speed. The relationships between mean wind speeds and both trend components and standard deviations of galloping in turbulent flows closely correspond to those relationships during the smooth flow, and they can be obtained using the average time of 10 times the shortest vibration period of the transmission line. That is, the response values of transmission lines in the smooth flow can be utilized to estimate gallopings in turbulent flows. To estimate the maximum amplitude of a galloping, a peak factor of approximately 2.5 can be used. © 2000 Scripta Technica, Electr Eng Jpn, 131(3): 19–33, 2000

     

输电线路杆塔分流系数仿真计算

利用CDEGS软件针对220 kV/500 kV典型输电线路杆塔分别进行工频和雷电流模型的仿真计算,给出避雷线、杆塔地网、杆塔基础具体分流大小,分析影响杆塔分流系数的影响因素。     

考虑线路有功传输约束的静态电压稳定分析

在求解电压稳定临界点的过程中,考虑了线路有功传输的系统静态安全运行约束,将电压稳定临界点的求取转变为非线性规划问题,建立以求解负荷裕度为目标函数的数学模型.采用对初值要求不高的非线性原对偶内点法求解已知负荷增长方向上的电压稳定临界点,该方法能够考虑各种等式和不等式约束条件,具有较强的鲁棒性.比较了考虑线路有功传输约束与不考虑约束两种情况下的支路功率,找到其中的薄弱支路.最后通过IEEE-30节点系统的仿真计算,验证了该模型及算法的有效性.     

基于GIS平台对线路避雷器应用方案的研究

雷害是造成输电线路故障的主要原因.根据对110 kV及以上电压等级输电线路雷害事故发展过程的研究,使用线路避雷器将有效降低雷击跳闸率.介绍了基于GIS平台结合微地形情况的线路避雷器安装选点,提出了线路避雷器的应用方案,结合某220 kV架空输电线路进行实例分析,研究表明此方案直观、形象且易于对防雷措施进行管理,对实际防雷工程有参考价值.     

增城110 kV线路避雷器运行效果分析

分析了线路避雷器的防雷原理．根据易遭受雷击的110kV线路采用复合绝缘外套金属氧化物避雷器后的实际运行情况,对避雷器投运前后线路跳闸数据进行分析对比。从而说明了线路避雷器确实具有一定的防雷效果。最后对线路避雷器的一些使用问题提出了建议。     

黑龙江省电网架空输电线路舞动分布研究

为预防由于线路舞动而造成跳闸问题,基于2000-2010年黑龙江省电网架空输电线路舞动次数、运行经验、地形地貌及气象等因素基础上,对黑龙江省电网架空输电线路舞动区域进行等级划分,并绘制舞动分布图,以保证线路安全运行.     

用于特高压输电线保护的能量方向元件

传统能量方向元件在特高压线路中不能正确判别故障方向,同时当线路出口发生故障时由于系统内阻很小而导致有功能量方向元件也不能做出正确的判断。提出了一种应用于特高压长距离输电线路的故障分量式能量方向元件,并且提出了相应的方向纵联保护原理,用贝瑞隆算法加以实现;从而使保护的可靠性大大提高;分析了保护判据及其动作特性。通过数字仿真证明了所提方向元件原理和保护判据的正确性和可靠性,该元件具有不受系统暂态过程、过渡电阻、串补电容等因素影响的特性,而且其灵敏度不受故障类型及故障位置等因素的影响,同时动作速度也较快,不大于20ms。     

一种考虑对各种误差综合修正的线路双端测距算法

在输电线路故障测距的研究中,由于线路参数可能变化或提供的参数不准确,以及其他不利因素的存在,对故障测距的精度会产生很大的影响.该文提出了一种基于分布参数模型和等效参数估计的双端测距算法,该算法只利用故障前的电压电流,在线估计出线路等效参数,对各种误差能够起到综合补偿的效果,从而提高了测距精度.EMTP仿真结果表明,该算法较之不带参数修正的算法测距精度有明显提高,具有很强的参数自适应能力和收敛能力.     

Measurement method using coupled transmission lines for voltage transients on the distribution line

It is well known that voltage transients are caused by the operation of switchgears in a power system. The voltage transients travel along the power line as a traveling wave, and cause malfunction of electrical devices, communication systems, and the operational error of a control system. The voltage transients at the making operation of switchgear were examined to obtain the fundamental data for considering the immunity of communication systems used on a power system. However, it was difficult to observe the voltage transients using the potential transformer and the capacitance potential device because the transients were very rapid. Therefore, a measurement method using the coupled transmission line system is proposed to measure the high-speed and high-voltage transients, and the actual experimental results on the 6.9-kV power system are presented. This method enables the measurement of high-speed voltage transients in out of contact with the power system.