Modeling of gas-insulated shunt reactor for high-frequency surge analysis

In this paper, we propose a circuit model of gas-insulated shunt reactors for surge analyses in high-frequency regions. The interleaved disk winding, widely used for high-voltage windings, has resonance phenomena in the high-frequency region and its series capacitance decreases above the resonant frequency. In order to simulate this phenomenon, an equivalent circuit composed of three-stage LC parallel circuits was proposed. On the contrary, the continuous disk winding can be simulated by one-stage LC parallel circuit because its series capacitance is almost constant through to the high-frequency region. Impedance characteristics of a full-scale model for a reactor winding were measured and the proposed circuit model was evaluated by comparing the measured results with the calculated ones. It was verified that the proposed model could represent well the winding impedance up to 10 MHz. © 1998 Scripta Technica, Electr Eng Jpn, 123(2): 32–39, 1998     

浪涌(冲击)抗扰度试验与瞬态过电压试验的对比与分析

介绍了浪涌(冲击)抗扰度试验和瞬态过电压试验两项试验的试验目的、试验原理、试验方法进行了比较分析,提出了一个新的瞬态过电压试验的合格判定方法.     

Dielectric characteristics of turn-to-turn insulation models of gas-insulated transformer under very fast transient voltages

This paper deals with the partial discharge inception voltage (PDIV) and breakdown voltage (BDV) characteristics of turn-to-turn insulation models for SF₆ gas-insulated transformers in the presence of steep-front short-pulse voltages, whose waveforms are 35/65 ns and 50/370 ns. It was determined that PDIV at nanosecond pulses were 1.05 to 1.15 times higher than those at standard impulse voltages and that the BDV at nanosecond pulses were about 1.4 times higher than those at standard impulse voltages. The ratio of impulse PDIV to ac PDIV is 1.40 to 1.48 for standard impulse voltages and 1.32 to 1.37 for switching impulses. © 1998 Scripta Technica, Inc. Electr Eng Jpn, 121(3): 36–43, 1997     

Implementation of the shunt harmonic voltages compensation approach

Instead of injecting harmonic currents to compensate those drawn by distorting loads, in this paper a shunt active filter is used for generating harmonic voltages to compensate harmonic voltages at the point of common coupling; the main advantage in using such a compensation approach is that, when the aim is to reduce or eliminate the harmonic voltages at the point of common coupling only one active filter is required. For determining the harmonic voltages such a filter must generate, two simple and practical methods are proposed in this paper; the effectiveness of these methods was evaluated using a 1-kW prototype of an active filter operating according to the shunt harmonic voltage compensation approach. In addition, the laboratory results were comparable to those obtained with the ATP-EMTP simulation software.     

高压并联电抗器器身-油箱间振动控制与仿真分析

高压并联电抗器运行时产生高水平振动与噪声,器身与油箱间的振动传递是导致噪声过高的原因之一.本文以氟橡胶和氢化丁腈橡胶为主要原料,设计了一种器身-油箱间三维隔振装置,振动试验台测试结果表明,其50～800 Hz隔振效率达到90％以上,经加速老化试验验证,可在电抗器油浸环境内服役13.6年.随后,针对某6.7 MV·A电抗...     

Comparative measurement of surge arrester residual voltages by D-dot probes and dividers

This paper presents the design and testing of coaxial D-dot probes with three different designs, namely, totally closed, totally open and semi-open designs. The latter design gives a good response and has an easy-access assembly for fixing and replacing the surge arresters (SA) under test. Simultaneous measurements of residual voltage for 9-kV SA are conducted by the designed probes, and resistive and universal dividers (RD and MRCD). The divider compensation principle is also introduced and implemented for both dividers. Both perfectly compensated dividers and the designed D-dot probes have an error of about 2.5% in the SA residual voltage due to the unavoidable resistance of connecting leads. SA residual voltages measured by uncompensated short MCRD divider give good agreement with that measured by the D-dot probe. The former has small inductive overshoot which can be neglected as the residual voltage crests before the discharge current by a few microseconds.     

特高压双回线路并联电抗器中性点小电抗的优化设计

对特高压同塔双回线路中的并联电抗器中性点接小电抗补偿潜供电流的方法进行了研究,分析了该方法补偿潜供电流的原理,得到了4种不同补偿方案下的中性点小电抗的计算公式.以淮南一上海的同塔双回特高压输电线路为例,针对实际线路中的所采用补偿方案,确定出中性点小电抗的取值范围.使用PSCAD/EMTDC仿真软件搭建数学模型,通过计算潜供电流、熄弧时间等主要的技术指标,从中选出抑制潜供电流效果最好的一组中性点小电抗参数.使用优选出的参数,分别对4种方案在不同故障类型、不同故障点位置的潜供电流进行综合比较分析,得到一种最优的补偿方案.并结合补偿效果和经济性,推荐了混合补偿方案,给设计者提供一个有价值的参考.     

Re‐ignition surge and high‐frequency arc extinction phenomena at 550‐kV shunt reactor current interruption

At substations connected with transmission lines and cables, shunt reactors are sometimes installed to compensate the capacitive current of these lines and cables. It is known that re‐ignitions occur and high‐frequency currents flow during interruption of the shunt reactor currents by switches. When the high‐frequency currents are interrupted immediately after the re‐ignitions (which is called high‐frequency arc extinction), the result is often repetitive re‐ignitions or voltage escalations that produce dangerous overvoltages. The authors investigated the occurrence of high‐frequency arc extinctions in a 550‐kV one‐break SF₆ gas circuit breaker during interruption of a 550‐kV shunt reactor current. Computations for a real 550‐kV substation gave a minimum frequency of 290 kHz for the high‐frequency current. However, 550‐kV reactor current interruption tests showed that high‐frequency arc extinctions did not occur even when this frequency was lowered to 26 kHz. Since high‐frequency arc extinction is generally likely to occur at lower frequencies, it was concluded that high‐frequency arc extinction will not occur in a 550‐kV one‐break SF₆ gas circuit breaker during interruption of shunt reactor current in real substations. © 2001 Scripta Technica, Electr Eng Jpn, 136(2): 18–25, 2001     

SF6电气绝缘设备故障时气体特征分解物的检测及应用

SF6电气绝缘设备在电力系统中的应用越来越广泛,寻求设备故障判断的有效检测手段和判断方法,对设备状态监测尤其重要。介绍SF6电气绝缘设备故障时的气体特征分解物的组成、故障判断经验和现场常用的几种检测方法,并从检测项目、测量范围、最小检测量及检测方式等方面对各检测方法进行应用分析,为有效、准确、快速判断电气设备故障类型及开展设备状态监测提供参考。建议将气体特征分解物检测纳入SF6电气绝缘设备预防性试验项目中。     

SF6电气绝缘设备故障时气体特征分解物的检测及应用

SF6电气绝缘设备在电力系统中的应用越来越广泛,寻求设备故障判断的有效检测手段和判断方。法,对设备状态监测尤其重要。介绍SF6电气绝缘设备故障时的气体特征分解物的组成、故障判断经验和现场常用的几种检测方法,并从检测项目、测量范围、最小检测量及检测方式等方面对各检测方法进行应用分析,为有效、准确、快速判断电气设备故障类型及开展设备状态监测提供参考。建议将气体特征分解物检测纳入SF6电气绝缘设备预防性试验项目中。     

WDK-600微机电抗器保护装置匝间保护原理分析

匝间保护是并联电抗器保护的主保护之一,可有效反应并联电抗器内部的匝间短路故障。WDK-600微机电抗器保护装置采用由电抗器高压零序电流、零序电压组成的零序阻抗继电器,弥补了以前阻抗补偿原理存在过补偿和欠补偿,补偿度难整定的不足。通过零序功率方向保护与零序阻抗保护的对比,介绍了WDK-600装置匝间保护的特点、基本原理、动作判据,不仅定性地分析了故障类型,而且从定量的角度分析了故障特征,为日后现场调试匝间保护提供借鉴作用。     

WDK-600微机电抗器保护装置匝间保护原理分析

匝间保护是并联电抗器保护的主保护之一,可有效反应并联电抗器内部的匝间短路故障.WDK-600微机电抗器保护装置采用由电抗器高压零序电流、零序电压组成的零序阻抗继电器,弥补了以前阻抗补偿原理存在过补偿和欠补偿,补偿度难整定的不足.通过零序功率方向保护与零序阻抗保护的对比,介绍了WDK-600装置匝间保护的特点、基本原理、动作判据,不仅定性地分析了故障类型,而且从定量的角度分析了故障特征,为日后现场调试匝间保护提供借鉴作用.     

真空断路器投切并联电抗器试验研究

为探明真空断路器投切并联电抗器时产生过电压的情况,并比较保护措施的效果,在运行电网上,对10kV真空断路器投切并联电抗器的实际运行进行了试验,在理论上进行了定性分析。证实：真空断路器投切电抗器时,将产生较高的过电压。为限制过电压,除按目前通行的措施安装氧化锌避雷器保护外,加装阻容吸收保护装置将更为有效。最后建议盘、柜制造厂宜生产投切并联电抗器专用的真空断路器柜,以备电力用户选用。     

Theoretical analysis of particle-initiated corona activities in hybrid gas-insulated transmission lines

This paper theoretically addresses the factors affecting the partial discharge activities due to metallic particles in hybrid gas-insulated transmission lines (HGITL) using the charge simulation method. There are two main reasons for using flexible HGITL. They are: (1) to overcome the technical problems and the huge cost associated with the on-site welding of large number of coaxial cylinders; and (2) to improve the utilization of the internal insulation system. The results are interpreted in terms of the basic principles of the streamer criterion in compressed gases, and also their trends are compared with those for other experimental works. The results reveal that HGITL have superior mitigation of the particle-initiated corona activities over the normal GITL, where the bundled HGITL have less improvement. The corona inception voltage decreases with the increase in the wire length, the surface charge density on the conductor insulation/spacers and the close proximity to charged or uncharged spacers, and with the decrease in pressure. On contrary, the number of occurrence of streamers and the integration of the effective ionization coefficient have opposite trends. Ribbed spacers are less sensitive to particle length and show a considerable improvement in the insulation reliability, especially when the rib becomes closer to the conductor insulation.     

Impact of shunt capacitor banks on substation surge environment andsurge arrester applications

The introduction of high voltage shunt capacitor banks on a power system can result in a number of overvoltage problems that tend to be associated with capacitor switching. The paper describes how proper application of surge arresters near a shunt capacitor bank requires careful analysis of the power system, the switching devices and their arrangements, the insulation level of nearby equipment, the type of grounding and the arrester energy dissipation duty     

补偿式感应电能传输模型建立及稳定性分析

交流感应电能传输系统根据法拉第电磁感应定律,通过空气介质实现了电能的无线传输,克服了以导线为媒介直接传输电能的缺陷,首先推导了一次侧谐振频率与二次侧负载电阻和一、二次侧感应耦合系数之间的关系模型,并对在回路无补偿、并联补偿情况下进行仿真,其次对一次侧电流和二次侧电压的幅频特性和相频特性进行了分析,确定影响系统传输效率的因素,验证了在一次侧补偿电路和二次侧补偿电路同时发生谐振时,系统传输效率最高。同时设计了交流感应电能传输系统传输变换器并应用Multisim 10软件对控制器进行了仿真,确定了这一方法的正确性。     

气体绝缘输电线路技术及其应用

气体绝缘输电线路(GIL)是类似GIS(气体绝缘金属封闭组合电器)封闭母线的气体绝缘大容量输电设备,其电气特性与架空线路相似且具有占地空间小等优点。介绍GIL的制造厂家、国际标准、基本结构和安装方式,分析GIL具有的输送容量大、损耗小、对环境影响小、可靠性和安全性高等技术优势,并介绍GIL在国内外的典型应用实例,为其在国内的更广泛应用提供参考。     

拉紧螺杆对并联电抗器的振动影响分析

并联电抗器在制造过程中通常采用拉紧螺杆紧固铁心,螺杆外加的压紧力不仅会影响硅钢片的磁特性,还会影响并联电抗器的振动特性.但是现阶段的研究并没有考虑压紧力对磁特性的影响,也没有考虑拉紧螺杆对并联电抗器的振动影响.针对这一现象,本文首先设计了考虑外加压紧力的磁特性测量系统,对硅钢片的磁化方向施加压紧力并进行磁特性测量.然后...     

Thermal and magnetic analyses of gas-insulated lines

This paper presents the factors affecting current rating “ampacity” of buried three-phase, naturally cooled isolated-phase gas-insulated lines (GIL) with flat formation and finite-element simulation of double-circuit, three-phase GIL inside a tunnel to calculate the magnetic-flux and current densities. In the former analysis, the depth of GIL burial, interspacing of phases and soil thermal resistivity are investigated to show their impacts on the GIL ampacity. In the latter analysis, the effects of electrical and physical arrangements of GIL phases on the magnetic-flux density inside and outside the tunnel, and the current density in few installed liquefied natural gas (LNG) pipelines, which run in parallel to the GIL inside the tunnel, are also studied. In any GIL configuration, the magnetic field impact is always extremely low. Localized hot spots along the periphery of the GIL enclosure are found and corrosion can be accelerated due to temperature gradient. Moreover, there is a possibility of galvanic corrosion of the enclosures when they are bonded together and with the gallery steel reinforcement at very short length intervals. The simulation results also give the best location of the LNG pipelines or any cables to have the lowest electromagnetic induction. The configuration that has the best “magnetic behavior” is distant-placed arrangement (DPA) with (abc–cba) phase arrangement. The induced eddy-current density in the LNG pipelines is very low and hence its thermal effects can be neglected.