交流断路器低频开断等效试验方法设计与实施

<正>断路器开断低频率电流的工况日益增加，目前包括中远距离海上风电低频输电线路用高压交流开关设备、发电机保护断路器及直流换流站阀侧断路器等均对大容量低频开断能力提出要求。然而国内外大多数用于大容量试验的短路发电机运行频率为50 Hz/60 Hz，因此，研究适合低频条件下的等效短路试验具有重要的现实意义。     

换流站交流断路器重合闸开断失败分析

近年来我国大力发展直流输电技术,由于发电厂和直流换流站断路器重合闸配合的特殊性,当发生单相接地故障时,发电厂侧断路器重合闸后,会出现断路器开断失败的问题。针对某500kV换流站中出现的断路器开断失败故障,运用电磁暂态仿真程序EMTP建立仿真模型,研究了断路器开断失败的原因。研究表明：故障发生时,流过换流站侧断路器的故障电流含有较大直流分量,影响了断路器的开断。     

分频输电系统及其应用

分频输电系统(fractional frequency transmissionsystem,FFTS)利用较低的频率(如50/3 Hz)传输电能,从而减少交流输电线路电气距离,提高系统传输能力。在水电、风电等可再生能源发电系统中,由于发电机转速较低,十分适合于利用分频进行发电和输电,在并网时转换为工频。首先介绍了分频输电的原理、并网特点等。其次,利用2个案例对水电、风电经分频输电并网的可行性进行了分析。特别是对分频风力发/输电系统的优越性进行了阐述。结果表明,水电、风电经分频输电并网是一种具有经济与技术优势的方案,在可再生能源发输电领域有着很好的应用前景。     

高压断路器的分闸控制电路及分闸时间的测量方法

高压断路器的分合闸时间直接影响断路器的开断和关合,是断路器的重要参数之一。分闸时间如果太长,会影响灭弧开断。因此,国家电网公司生产输电[2004]40号文件《预防交流高压开关事故措施》对新装设备和检修后开关设备的技术措施第3条明确规定：“断路器机械特性是检修调试断路器的重要质量指标,也是直接影响开断和关合性能的关键技术措施。     

风电经分频输电并网系统穿透能力计算方法研究

风电经分频输电并网是一种全新的风电并网方案。在对该系统结构及优点进行介绍的基础上,提出了一种基于静态安全约束的穿越功率极限计算方法。该方法可以应用于常规风电并网系统以及风电经分频输电并网系统。最后,在RTS24节点测试系统中对3种风电并网方案进行分析,对其风电穿透能力进行了对比。分析结果表明,与风电就近并入电网边界相比,利用分频或者工频传输系统将风电传输至负荷中心可以数倍地提高风电的穿越功率极限的结论。由此可见,分频输电系统为风电并网提供了一种全新的方案,具有经济与技术优势,在大型风电场中有着很好的应用前景。     

双断口真空断路器开断能力的探讨

论述了提高双断口真空断路器开断能力的原理 ,比较了双断口和单断口真空断路器的开断能力。实验结果表明 ,双断口真空断路器的开断能力较单断口高 2倍。讨论了均压电容对开断能力的影响 ,提出了对操动机构的要求 ,最后 ,介绍了多断口真空断路器的优点。     

动态延时分相顺序控制的断路器合闸新方法

针对超高压输电线路并联电抗器引起的直流偏置电流制约断路器开断灭弧,设计了断路器顺序合闸控制原理及相应装置,提出动态延时分相顺序合闸的新方法,适用于电力系统中变电站、发电厂的分相控制断路器特殊目的的合闸控制.经过工厂试验和工程验证,该方案能有效解决输电线路偏置电流影响断路器灭弧的难题。     

一种强制换流型混合直流断路器方案

作为高压直流输电的关键设备之一,直流断路器受到了广泛的关注。混合直流断路器继承了机械断路器通态损耗低与固态断路器开断迅速的特点,是目前直流断路器研究的主要方向。文中着重分析了影响基于全控型电力电子器件的强制换流型混合直流断路器开断速度的因素,针对辅助换流电路中缓冲电容放电回流影响机械断路器动作时间以及能量吸收电路吸收能量的时间问题,提出一种强制换流型混合断路器方案,该方案能够防止缓冲电容电流回流,同时减少避雷器吸收能量所用时间。对该断路器各个工作阶段的数学模型进行了数值分析,通过Pscad/EMTDC软件对故障状态混合断路器开断过程进行仿真,并且与典型强制混合直流断路器开断过程进行比较,验证了该方案切实可行。     

高压直流断路器系统开断条件仿真研究

为分析高压直流断路器在实际高压直流输电系统中的各种故障情况及其开断条件,笔者利用PSCAD/EMTDC仿真软件,根据高压直流输电系统的结构和控制方式,搭建了背靠背高压直流输电系统仿真模型。仿真研究了单端高压直流输电系统不同位置发生单相、异相、三相及直流母线短路等故障情况下的暂态特性。仿真结果表明,该仿真模型有很好的动态响应特性,能够有效模拟单端高压直流输电系统的各种短路情况。同时,结合高压直流系统的控制方式对各种短路情况进行了研究分析,找出了在系统中对高压直流断路器的开断较为苛刻的情况。经过参数分析得到了各种不同故障情况下对直流断路器的开断影响较大的故障电流峰值、最大故障电流上升率等系统参数。从而为多端高压直流输电网络建模分析、高压直流断路器型式试验及其标准的制定、高压直流断路器的发展提供借鉴。     

高压直流真空断路器安全开距的试验研究

高压直流断路器是保护直流输电系统的重要组成部分,机械式高压直流真空断路器是目前几种可行方案之一。断路器的安全开距是断路器重要的开断参数,临界开距是直流真空断路器确定换流时刻的依据,直接决定其开断性能。该文建立了基于换流的直流真空断路器安全开距试验系统,主开关和换流开关均选用电磁斥力机构,直流试验电流源由低频LC振荡电路近似。应用PSCAD对该系统的开断过程进行仿真,以验证参数设计的可行性。试验中系统开断模拟直流电流为4 kA,采用位移传感器对动触头轨迹进行检测,得到动触头的分闸速度约为2.4m/s。对比仿真与试验波形,分析了与熄弧时间对应的开距对开断能力的影响,通过试验得到最快熄弧时间和临界开距,其值分别为为0.9 ms和2.2 mm。试验结果对高压直流真空断路器确定换流时刻具有参考价值。     

Improvement of thermal interruption capability in self‐blast interrupting chamber for new 245‐kV 50‐kA GCB

Current zero measurements are performed for 245 kV‐50 kA‐60 Hz short line fault (L90) interruption tests with a self‐blast interrupting chamber (double‐volume system) which has the interrupting capability up to 245 kV‐50 kA‐50 Hz L90. Lower L90 interruption capability is observed for longer arcing time although very high pressure rise is obtained. It may be caused by higher blowing temperature and lower blowing density for longer arcing time. Interruption criteria and an optimization method of the chamber design are discussed to improve L90 interruption capability with it. The new chambers are designed at 245 kV‐50 kA‐60 Hz to improve gas density in thermal volume for long arcing time. 245 kV‐50 kA‐60 Hz L90 interruptions are performed with the new chamber. The suggested optimization method is an efficient tool for the self‐blast interrupting chamber design although study of computing methods is required to calculate arc conductance around current zero as a direct criterion for L90 interruption capability with higher accuracy. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(1): 9–17, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20743     

真空断路器电磁瞬态仿真模型的研究与应用

由于真空断路器具有优良的开断和绝缘恢复性能，因此，可用来开断由于电弧不稳定而产生的高频电流。在一定的电网奈件下，在开断高频电流的过程中可能引起多次重燃和严重的过电压。本文的主要目的是用PSCAD建立真空断路器模型来展现断路器的真实特性。这个模型融合了燃弧时间、截流，介质恢复强度及断路器的熄弧能力等所有本质特性。采用开断实用的电炉用变压器来检验本文所开发的三相真空断路器的模型。并提供了检验结果。     

History of vacuum circuit breakers and recent developments in Japan

Vacuum circuit breakers (VCBs) have been developed and widely applied in Japan to meet the requirements of increasing energy consumption and also in national security of various areas. As a result, for example, a 168 kV two break porcelain type and a 100 kA one break VCB have already appeared in the Japanese market and they are currently being exported to world-wide markets. VCBs interrupt currents in vacuum, and this means they do not exhaust dissolved gases which are sometimes harmful to the human body or cause effects on the environment. Therefore, by its nature, the recycling of materials and safety to the human body have been realized, and also no global warming effects would be expected. Energy is extremely essential and important in human daily life, and many types of circuit breakers play important roles in electrical power transmission and distribution systems to maintain the systems reliability and safety by switching the systems under several conditions. Since vacuum circuit breakers possess a lot of advantages such as high current interrupting capabilities, small size, and low cost, they will be used much more in the future, and at this moment, we believe it is very worthy to discuss and consider thoroughly future trends of VCBs. In this paper, the results of the developments in Japan will be reviewed, the reflection of the results will be stated, and the subjects of engineering in the 21st century will be discussed. These will include recycling, safeguards to the human body and the fireless nature of VCBs; and it will be demonstrated that the developmental works of VCBs are being wonderfully explored in Japan now and in the future.     

分频输电系统的实验研究

分频输电是一种非常有竞争力的远距离输电方式。该文介绍了分频输电系统实验装置的构成和初步实验结果。该实验首次利用交．交变频器作为倍频器，将50/3Hz电能转换为50Hz电能向工频系统送电，成功地实现了一种新型(FACTS)柔性交流输电装置。文中还介绍了分频系统和工频系统的并网情况，分析了分频输电系统实验的波形、效率、功率因数等相关数据。实验表明：对于一回1200km的500kV输电线路，利用分频输电系统可以使其输送能力达到2000MW，证明了这种新型FACTS装置的巨大应用潜力；分频输电在750kV及以下电压等级的实际工程中应用不存在技术上的困难。     

Comparison of synthetic test circuits for ultra-high-voltagecircuit breakers

Three synthetic test circuits to verify the interrupting performance of UHV circuit breakers (765kV, 63kA, 50Hz) are compared on aspects of equivalence, operation, required capacitive energy and applicability. The comparisons show that, although each circuit has its own merits, the EPIC circuit appears to be very attractive. The EPIC circuit not only saves on capacitive energy but has also a good equivalence with the direct test circuit     

电磁环网条件下西北750 kV电网运行方式的研究

随着西北750 kV电网的建成投运,原有330 kV网架将与新出现的750 kV线路形成电磁环网。文中研究了2008年底西北750 kV骨干网架初步形成后,750/330 kV电磁环网运行方式对系统安全稳定性的影响。静态安全分析和稳定计算结果表明,在未形成坚强的750 kV网架结构前,合环运行比解环方式更有利于提高西北电网输送能力和稳定水平。针对合环运行可能出现的系统振荡、输送受限等问题,提出通过加强安稳装置配置、研制遮断容量更大的断路器、优化运行方式和网架结构等措施来保证系统的稳定运行。     

横磁触头真空电弧起始运动的临界触头开距实验研究

起始桥柱状真空电弧运动的临界开距是对应于横磁触头大电流真空电弧运动模式演变的标志性物理量,对横磁触头真空断路器大电流开断性能具有重要影响。本文的研究目标是实验研究横磁触头开槽方式、燃弧时间和电弧电流等因素对横磁触头起始桥柱状真空电弧运动临界开距的影响规律。研究结果显示在燃弧时间0 ms~10 ms、电流有效值5 kA~31.5 kA的实验条件下,3种结构的横磁触头的起始桥柱状电弧有越靠近电流峰值起弧,停滞时间越长的趋势。直角槽型卐字形横磁触头（CuCr40）、螺旋槽型横磁触头（CuCr25）和曲线槽型卐字形横磁触头（CuCr50）的电弧运动临界开距分别在0.96,1.1 mm 和1.7 mm有概率最大值点。相关研究结果对横磁触头大电流真空电弧的发展和演变特性的理解提供基础。     

EMTP simulation of SLF interrupting performance for two serially connected arcs with different arc parameters

This paper shows the calculation of SLF interrupting performance for two serially connected Mayr‐type arc models with different arc parameters by using EMTP‐ATP Models. Arc model 1, assuming an air circuit breaker, has large arc time constant and large arc power loss. Arc model 2, assuming a vacuum circuit breaker, has small arc time constant and small arc power loss. It was not possible for arc model 1 to interrupt 300 kV‐63 kA‐90% SLF by itself. However, by connecting these arc models in series, interruption became successful, even if arc model 2 was reignited at low voltage a few microseconds after current zero. These computations suggested that serial connection of the two circuit breakers with different breaking characteristics would give a totally excellent circuit breaker by making the best use of advantages of each circuit breaker. EMTP‐ATP Models were very useful in solving the arc models, which are expressed by differential equations and coupled with the electric circuit. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(4): 25–33, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10020     

Fundamental studies on vacuum circuit breaker arc quenching limitswith a synthetic test circuit

The aim of this work is to demonstrate the use of a synthetic test circuit with LC resonant circuits for fundamental experimental work on CB (vacuum circuit breakers). Studies have been performed on a 36 kV-model CB at test currents of 5 and 10 kA r.m.s. aimed at separating the influence of different parameters of the transient recovery voltage such as average rate of rise and peak value on the breaking capability. Furthermore, the effect of the arcing time on the measured arc quenching limit is presented