High frequency transients and electromagnetic interference within 69 kV substations

This paper presents an analysis of the experimental measurements of fast transients and their electromagnetic interference on the protection system in air isolated distribution substations. Transients were recorded in the relay inputs of potential and current transformers due to switching operations in a 69 kV bus bar. A peak overvoltage of up to 6.5 kV and frequencies of around 1 MHz and above, were recorded in secondary circuits that are rated 115 V. The current presented fast transients with relatively small amplitudes and lower frequencies than the recorded voltages. The transients caused relay failures leading to the unnecessary disconnection of the substation. Transients are supposed to be related to radiated and conducted interferences caused by the electric arc during switching operations. Transient voltage and currents are analyzed, and the results are compared with others from the literature. Some solutions are presented to mitigate the failures of the protection relays.     

关于500kV变电站工频电磁场强度的研究

根据500 kV变电站工频电磁场强度现场测试情况,对500 kV变电站工作场所和设备的工频电场和磁场强度进行研究,得出电场和磁场强度的分布规律及特点。从保障作业人员和公众健康、促进企业安全经济运行的角度,提出电磁场防护的措施及管理办法。     

Reduction of the edge steepness of electromagnetic surges in gas-insulated substations

Contents In this paper a methodology for reducing the edge steepness of electromagnetic surges in gas-insulated substations is presented. The damping of the waves results from the utilization of the skin effect by means of a semiconducting coating of the substation's inner conductor. An analytical calculation of the attenuation factor shows the behaviour of a surge's different frequency portions. FDTD-simulations confirm the flattening of the wave fronts by the damping layer. Finally, a comparison with an uncoated structure shows the advantages of the coating.

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Verminderung der Flankensteilheit elektromagnetischer Sprungwellen in gasisolierten Schaltanlagen

Übersicht Es wird eine Möglichkeit zur Verminderung der Flankensteilheit von elektromagnetischen Wellen in gasisolierten Schaltanlagen vorgestellt. Die Dämpfung der Wellen erfolgt unter Ausnutzen des Skineffekts durch eine halbleitende Beschichtung des Innenleiters der Schaltanlage. Anhand einer analytischen Berechnung des Dämpfungskoeffizienten wird das Verhalten der unterschiedlichen Frequenzanteile der Sprungwellen aufgezeigt. FDTD-Simulationen bestätigen die Abflachung der Wellenstirn durch die Dämpfungsschicht. Abschließend zeigt ein Vergleich mit einer unbeschichteten Anordnung die Vorteile der Beschichtung auf.

     

关于城区高压变电站电磁辐射对周边居民生活和环境的影响

近年来，随着城区高压变电站电压等级的提高和城区居民对环境要求的提高，在现实生活中不少城区居民对电磁辐射产生了诸多的置疑和恐慌。为此。针对电磁辐射、高压变电站电磁辐射、国家环境卫生标准、电磁辐射防护措施等方面进行了论述，希望建立起一个对电磁辐射的科学认识，同时呼吁有关部门加强对电磁辐射的研究和宣传力度。     

Reduction of low voltage power cables electromagnetic field emission in MV/LV substations

In this paper a solution to reduce magnetic field emission levels generated by MV/LV substation power cables is proposed. The reduction is obtained by the arrangement of the phases in a proper way and by shielding the cables with magnetic or conductive materials. The effects introduced by these two options have been analyzed by means of simulations, using finite elements method calculation software, and by experimental measurements. The introduced results allow selecting an optimal arrangement and the best screening material in order to reduce the magnetic fields in those directions required to protect.     

瞬态电磁场辐射敏感度测试系统

随着科学技术的发展,各种电子设备大量使用,电磁干扰成为关注的焦点,要进行电磁干扰实验首先必须建立模拟电磁场.本文介绍了可以模拟核电磁脉冲的瞬态电磁场辐射敏感度测试系统,论述了该测试系统建立的必要性、功能、系统组成及使用方法.     

Mitigation of switching‐induced transient electromagnetic interference on control cable using Ni–Zn ferrite rings over cable sheath in gas‐insulated substations

The transient electromagnetic fields during switching operation in gas‐insulated substations (GISs) have rise times on the order of nanoseconds. These fields leak into the external environment through the discontinuities of gas‐insulated modules and affect the control cables and induce the transient voltage on cables, which results in malfunctioning of the equipment. The amplitudes of the electric and magnetic fields could be a few tens of kilovolts per meter and a few hundred amperes per meter according to layout of GIS, respectively. In this work, the induced voltage in the central conductor of a control cable and the induced current in its sheath, which is parallel to bus duct in a GIS with rated voltage of 230 kV, are calculated. Influence of the sheath material on the induced voltage and the type of its grounding on the induced current are analyzed. Furthermore, the impact of installing ferrite rings over the control cable sheath in mitigating the induced voltage and current is investigated. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

变电站二次电缆瞬态电磁骚扰的特征统计方法与不确定度分析

针对瞬态电磁骚扰数据样本量小和分散性强的特点,结合自助统计法,提出了偏差矫正的自助置信区间估计法和多次测量不确定度的B类评估方法。首先在变电站测量了开关操作时二次电缆端口的瞬态电磁骚扰,其次应用基于自助法的随机加权原理和偏差矫正的自助置信区间估计法,得到特征参数的统计均值和置信区间。然后应用瞬态电磁骚扰多次测量不确定度的B类评估方法,得到了特征参数的不确定度。最后评估标准波形特征参数与实测波形的符合性。分析结果表明：多次测量骚扰电压峰峰值的分散性是产生不确定度的主要因素;100~300 kHz区间实测骚扰电压的上升时间显著长于100 kHz慢速阻尼振荡波;6.5~10 MHz区间实测骚扰电压的上升时间显著长于快速阻尼振荡波;实测骚扰电压波形随区间频率的增加,持续时间缩短。     

继电保护装置的电磁干扰实例分析

随着微机型继电保护的广泛应用,继电保护装置和二次回路的电磁干扰问题越来越引起电力工程界的重视.该文分析了电力系统中常见的电磁干扰,讨论了继电保护的常见干扰源、耦合途径和抑制手段,对实际工程中发生的两起继电保护电磁干扰问题进行了深入的研究,分析了干扰产生的原因,提出了相应的现场处理意见,具有一定的理论意义和工程实用价值.     

继电保护装置的电磁干扰实例分析

随着微机型继电保护的广泛应用,继电保护装置和二次回路的电磁干扰问题越来越引起电力工程界的重视。该文分析了电力系统中常见的电磁干扰,讨论了继电保护的常见干扰源、耦合途径和抑制手段,对实际工程中发生的两起继电保护电磁干扰问题进行了深入的研究,分析了干扰产生的原因,提出了相应的现场处理意见,具有一定的理论意义和工程实用价值。     

Transient electromagnetic plane wave reflection from a dielectricslab

Reflection of a transient plane wave normally incident upon a lossless dielectric slab is analyzed via the Fourier transform. The exact expression for the time-harmonic field is used in the inverse Fourier transform to obtain the transient response to a class of exponential exciting functions. Cauchy's integral theorem and the Poisson sum formula yield closed-form expressions for the unit step and impulse response functions     

航空单相交流电源电磁干扰分析和抑制

本文以飞机的单相交流电源为例,分析航空单相交流电源的工作环境,找出导致交流电源产生电磁干扰的原因,给出抑制交流电源电磁干扰的原理和方法.在不改动总体设计的基础上,针对实际情况提出屏蔽、搭接和滤波等电磁干扰抑制措施,并重点对滤波技术进行了讨论.     

集中监控中心站电磁干扰影响的分析与控制

分析了集中监控中心站在运行中存在的各种电磁干扰源 ,对这些干扰源对微机保护、微机监控及工作人员可能造成的危害 ,提出了消除这些危害的切实可行的措施。相应措施亦适应无人值班变电站。     

重频电磁脉冲对氢闸流管触发影响的研究

以氢闸流管栅极触发电路为研究对象,建立了共地耦合干扰模型,并进行了栅极共地耦合电磁干扰研究,实验在重复频率电磁脉冲(EMP)环境下进行。结果表明,重复频率电磁脉冲的传导干扰对氢闸流管的触发系统产生影响,其数量增多与间隔减小均使误触发的可能性增大。对比理论分析与实验结果,认为电磁脉冲的数量增多与间隔减小均可导致传导干扰增强从而使氢闸流管误触发趋势增大。     

开关电源的电磁干扰产生原因及抑制方法

由于开关电源本身的工作特性使得电磁干扰问题相当突出,其干扰信号经传导和辐射对电子设备、通信系统等产生电磁污染.从电磁干扰产生的机理人手,着重论述了开关电源中的整流电路电流断续、功率开天管的高速开关动作瞬间的电压、电流瞬间变化时产生电磁干扰的原因以及电磁干扰的危害,总结了不同场合下最大限度地抑制电磁干扰的方法和措施.提出了抑制电路设计参数的估算关系式,经仿真实验抑制电路对电磁干扰抑制效果明显.     

Smart industrial substations

The smart industrial substations enhances plant electrical personnel safety by physically removing the operator from the arc flash zone. The smart industrial substations shifts electrical technician functions from time-consuming tasks in front of substations equipments to time-saving tasks away from the substations. The smart industrial substation is a "best fit" integration of traditional and modern substation devices with local/remote human-machine interfaces (HMIs), pagers, and cell phones.     

一起由于电磁干扰造成断路器误合闸的事故分析

对一起由于测控装置同期开入回路受到电磁干扰后误动,造成主变压器中压侧断路器误合闸的严重事故进行了详细分析,并说明了电磁干扰使得光耦元件“瞬态饱和”的现象和原理,指出了测控装置设计不当的地方,并由制造厂家进行了改进。     

矿用变频器辐射电磁干扰特性分析

为了研究矿用变频器运行状态下电磁辐射分布特性,基于以电压源型两电平变频器为核心的调速系统,在分析调速系统工作机理与干扰源的基础上,采用矩量法和天线理论相结合的方式,在电磁场仿真软件FEKO中搭建了变频器天线模型.通过模型仿真结果,分析了调速系统稳态下的干扰特性.研究结果表明:变频器外壳起到了很好的屏蔽作用,内部电磁干扰...     

高压直流接地极对管道电磁阀的干扰影响研究

针对高压直流输电(HVDC)接地极处于单极大地回路运行工况下,很大的入地杂散电流可能产生电磁阀发生误动作的风险,影响管道正常运行。建立了传导干扰对电磁阀线圈影响的数学模型,研究了直流杂散电流引起电磁阀误动作的机制。采用数值模拟的方法,建立国内某1 100 kV特高压直流输电工程接地极对附近管道干扰的仿真模型,并设计了管地电位实时数据采集系统。仿真及现场测试结果表明,干扰电压以接地极距离管道最近位置为中心,依次向上下游递减;冬季电磁阀受到的直流干扰是夏季的3.43倍;仿真结果和实测结果基本吻合,误差在10%以内;沿管线增设4个和6个绝缘接头后使得管地电位差降低62.1%、71.4%。为可靠预防电磁阀异常工作,在冬季应该加强阀室巡检,并沿管道上下游适当位置安装绝缘接头。