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Takeyoshi Kato Yue-Jin Tang Hirotaka Shimizu Naoki Hayakawa Yasunobu Yokomizu Toshiro Matsumura Hitoshi Okubo Yukio Kito Toshiaki Nagafusa Seiichi Miyake Tomoyuki Kumano Masayuki Hatano Kazuhiko Sato Wataru Sato 《Electrical Engineering in Japan》1996,117(1):45-59
Superconducting technology is regarded as a breakthrough to future electric power transmission because of its highly densified and large transmission capability. This paper proposes a concept of the future power system composed of various superconducting apparatuses. A prototype model system called “PROMISE (PROspective power transmission Model system Integrated under Superconducting Environment)” is constructed to prove the realization of the above concept. PROMISE is composed of a superconducting transformer (60 Hz, 6/3 kV, 1000 kVA class), superconducting fault current limiter (6 kV, 200 A class), and superconducting power cable (5 m, 6 kV, 650 A class). This paper also shows that PROMISE realized the transmission of the electric power of 3.8 kV–460 kVA (50 Hz). This is the first achievement in the world. The voltage-current synthetic test verified that PROMISE can withstand ac voltage of 6 kV while carrying ac current of 170 A (60 Hz). The ac loss of superconducting cables, the heat leak of cryostat and the core loss of the superconducting transformer are measured to estimate the transmission loss of PROMISE. These fundamental performances of PROMISE may indicate the feasibility of the future introduction of superconducting technology for electric power systems. 相似文献
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与用于交流系统或双极直流系统的限流器不同,用于多端柔性直流系统的故障限流装置应能够在短路故障发生初期有效抑制故障电流的快速上升,避免在线路断路器动作之前换流器桥臂闭锁。针对这一性能要求提出了一种专门用于多端柔性直流电网中的新型超导故障限流器的基本结构和工作原理,并制作了原理验证样机。通过对原理验证样机开展的一系列实验,证明了设计结构与原理的可行性。实验结果也充分展示了这类限流器的功能特性,如其能充分利用铁芯的最大磁导率在短路故障发生的几个毫秒内实现最大限流感抗,从而有效抑制故障早期的短路电流上升率。此外,可以通过对超导隔离环组数量的调整,设定限流器的限流阈值,灵活适应不同直流系统的限流需求。 相似文献
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随着直流输电特别是多端直流输电技术的发展及广泛应用,多个换流器并联连接的接线方案得到越来越多的研究和应用。依托400 kV青海—西藏直流联网工程采用电磁暂态仿真的方法研究了2换流器并联结构与单换流器结构相比,在各种故障工况下系统过电压水平,以及阀避雷器、交流避雷器、中性母线避雷器、直流极线和6脉动中点避雷器电流、能量变化的规律。结果表明,在某些工况下,故障后过电压水平和避雷器电流、能量均有变化。发生换流变阀侧接地故障时,阀避雷器能量增加2倍以上,交流单相、三相接地故障后,交流避雷器能量增加60%,因此在绝缘配合设计时需要相应增加避雷器并联数量。所得研究结论可为多换流器并联结构过电压与绝缘配合设计提供参考。 相似文献
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In a power transmission cable system, the uniformly configuration of the cables between sections is sometimes difficult to achieve because of the geometrical limitation. This will cause the increase of sheath circulating current which results in the increase of sheath loss and the decrease of permissible current of the power transmission system. While the cable is on operation, because of cable aging and other unexpected reasons, sheath fault always occurs which leads to the further damage of the insulation layer and the life of the cable. These two problems were particularly addressed in this paper. Over last few years, two research groups in South Korea and the United Kingston have worked together extensively to solve these problems and made some great achievements. For tackling the problem of the increase of sheath circulating current, one special device was designed to measure this kind of current; an effective measure was proposed to reduce the current and the new measure was well protected from any further threats like cable fault and lightning. Regarding the problem with sheath fault, one data acquisition system was designed to monitor the sheath fault on field; a new fault phenomenon was discovered for the cable buried in sand; based on the new discovery, the fault was characterised, modelled and simulated; furthermore advanced signal processing techniques were introduced to extract the fault signals from the sheath, detect and locate the fault. These new solutions have either been successfully applied in practical operation of the power cable system or used in further research to propose more advanced solutions. The paper reviewed the latest developments of these new solutions. 相似文献
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超导故障限流器对限制短路电流和短路容量具有重要的研究意义。文中基于MgB2的特性,采用先变形后退火的方法,并利用特制高温玻璃纤维进行绝缘,在退火处理后再通过环氧树脂胶黏剂固化,研制了一台小体积电阻型超导故障限流器样机。同时通过液氦和氦气冷却,对其性能进行测试;通过建立电阻型超导故障限流器的一维热传导模型和电路方程,对其动作特性进行仿真。测试和仿真结果表明该样机限流效果明显,限流百分比可达44%以上,然而限流器的失超长度、超导线材温度和失超电阻随着时间呈非线性变化且限流器的线材并未全部失超。失超恢复时间约为1.5s,可通过交替连接方式满足重合闸需求。最后针对10kV电力系统,提出了MgB2的小体积电阻型超导故障限流器工程设计原理,并分析了其在工程应用中的可行性。 相似文献
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直流系统短路电流的限制与开断技术是直流输电技术发展的瓶颈。针对这一技术问题,文中在分析已有直流限流器和直流断路器拓扑的基础上,提出一种适用于直流系统的改进型故障电流限制器的拓扑结构,该设备利用直流断路器使用的电流转移原理分断电路,可在系统发生短路故障时快速限制短路电流的上升率及短路电流水平,有效保障内部的电力电子器件避免过电压而造成的损坏。通过在MATLAB/Simulink平台搭建仿真模型并进行故障限流的仿真,验证了限流器的功能和限流指标,仿真分析结果表明所提出的限流器具有良好的限流效果。 相似文献
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柔性直流输电具有灵活、可靠的特点,成为目前直流输电领域的研究热点。但直流电网中发生短路故障时其短路电流较大,如何在直流侧故障时快速将其切除成为直流输电技术的研究难点。文章重点研究了柔性直流输电系统中限流器的优化配置。以目前研究较多的超导限流器为例,对柔性直流电网中的故障问题进行详细分析;基于超导限流器的特性,提出了考虑直流断路器切断容量和故障反应时间的限流器优化方法;选取算例在MATLAB平台上对该优化方法进行了验证,仿真结果表明该优化配置方法能有效的指导限流器的设计,提高其应用过程中的经济性。 相似文献
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Tomonori Koyama Katsuyuki Kaiho Iwao Yamaguchi Satoru Yanabu 《Electrical Engineering in Japan》2011,175(3):12-19
Using a high‐temperature superconductor, we constructed and tested a model superconducting fault current limiter (SFCL). The superconductor and a vacuum interrupter serving as the commutation switch were connected in parallel using a bypass coil. When the fault current flows in this equipment, the superconductor is quenched and the current is then transferred to the parallel coil due to the voltage drop in the superconductor. This large current in the parallel coil actuates the magnetic repulsion mechanism of the vacuum interrupter and the current in the superconductor is interrupted. Using this equipment, the current flow time in the superconductor can easily be minimized. On the other hand, the fault current is also easily limited by the large reactance of the parallel coil. This system has many advantages. Thus, we introduced an electromagnetic repulsion switch. High‐speed reclosing after interrupting the fault current in the electrical power system is essential. Thus, the SFCL should recover to the superconducting state before high‐speed reclosing. But the superconductor generates heat at the time of quenching, and it takes time to recover to the superconducting state. Therefore, the recovery time is an issue. In this paper, we study the superconductor recovery time. We also propose an electromagnetic repulsion switch with a reclosing system. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 175(3): 12–19, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21072 相似文献
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中性点直接接地电网的自适应零序电流速断保护 总被引:2,自引:0,他引:2
为了尽可能减小线路零序电流速断保护的保护范围受系统运行方式变化等因素的影响,提出了一种自适应零序电流速断保护的实现方法。该方法假设输电线路两侧的保护之间具有通信通道,系统发生短路时线路两侧的保护能够实时计算出系统等值阻抗并经通信通道实时传送给对侧的保护,两侧的保护装置可根据短路类型实时调整零序电流速断保护的动作整定值。通过计算不同接地短路类型时零序电流速断保护灵敏度的公式,表明零序电流速断保护的保护范围不仅受系统运行方式变化的影响,还受接地短路类型的影响。仿真计算结果表明,文章提出的自适应式零序电流速断保护的实现方法可有效减小系统运行方式变化及短路类型不同对保护范围的影响,使保护的性能大大提高。 相似文献
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直流滤波器是直流输电工程直流场的重要设备之一.详细分析了直流滤波器避雷器配置方案及参数选择过程,给出了避雷器参数选择的具体表达式.研究了对直流滤波器绝缘水平起决定性作用的故障工况:直流极线接地短路、直流极线侵入操作波;建立了这2种故障工况计算模型,模型中需要考虑故障点到直流滤波器高压端之间的故障电感.基于具体±1100kV特高压直流输电工程,对直流滤波器设备进行过电压计算.计算结果给出了滤波器各设备的最大暂态过电压,进而根据绝缘裕度确定了该特高压直流工程直流滤波器各设备最终的绝缘水平,为设备选型和制造提供依据. 相似文献
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B. K. JOHNSON R. H. LASSETER F. L. ALVARADO D. M. DIVAN H. SINGH M. C. CHANDORKAR 《电力部件与系统》2013,41(6):629-645
ABSTRACT A new paradigm for electric power transmission based on high temperature superconducting dc. networks is studied as a feasible alternative to ac power transmission systems. The dc network operates at generation voltages allowing for direct connection of the generators to the rectifiers, eliminating the need for high voltage insulation and transformers. The overall system consists of a mesh connected, low voltage, high current dc superconducting transmission system, supplied by unit connected generators and feeding many small inverters to pass controlled levels of real and reactive power to ac loads. This paper introduces the concept of a superconducting dc mesh. Inverter topologies and control strategies required for interfacing the ac distribution systems to the dc mesh. The paper presents a conceptual overview of the operation of the system based on simulation studies. 相似文献
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柔性直流输电线路故障处理与保护技术评述 总被引:9,自引:6,他引:3
由于柔性直流输电系统调节方式和自身结构的特殊性,直流线路的故障电流具有上升速度快、峰值大的特点,极易损坏换流器件和设备绝缘,且柔性直流系统无法通过调节触发角实现故障自清除。因此,对直流线路故障处理和保护提出了更高要求。对于柔性直流线路故障,不仅需要快速且可靠的线路保护对故障进行识别,也需要相应的处理措施和手段对故障后的电流进行有效限制,以减少故障冲击电流对换流器件、直流线路自身以及系统的损害。基于柔性直流输电线路的故障特征,从直流线路故障电流抑制、减少故障影响、线路保护原理等方面,系统地介绍了国内、国外柔性直流输电线路故障处理与保护技术的现状和发展。重点分析了几种辅助电路、新型换流器拓扑和直流输电结构,以及直流断路器在处理直流线路故障方面的性能。探讨了目前柔性直流输电线路故障处理和保护亟须解决的关键问题以及未来进一步的研究方向。 相似文献
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超导故障限流器的应用研究新进展 总被引:20,自引:5,他引:15
在对原有超导限流器分类的基础上,论述了超导限流器在电力系统应用的最新进展及国内外的工程情况。着重介绍了电阻型、桥路型、桥路串阻型及全控桥型等几种具有较高应用价值的超导故障限流器的原理及特点,并对限流储能相结合的超导设备原理进行了探讨。最后,指出了超导限流器的未来发展趋势及面临的若干问题。 相似文献
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加强线路绝缘对变电站绝缘配合的影响 总被引:3,自引:0,他引:3
主要介绍了利用ATP和ATPdraw程序,对变电站及输电线路建立仿真计算模型,研究输电线路加强绝缘后,线路侵入波对变电站绝缘配合的影响,通过研究表明,针对湖南省电力系统现有的绝缘水平,220kV线路绝缘子调整至15片,500kV线路绝缘子调整至29片,对现有的绝缘配合不会形成威胁. 相似文献
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一般来说,托卡马克(EAST)装置中的NBI加热系统都是利用Snubber来实现保护的。为了优化Snubber的结构,通常都给其添加一个偏置直流源,将Snubber的性能维持在BH曲线的负饱和点附近,这样能使Snubber的质量减小一半。而目前普遍使用的偏置直流源是将50/60 Hz的交流电经过高压隔离变压器变压后整流直接得到。50/60 Hz的高压隔离变压器体积大、质量重,将带来移动不便和占用大量空间等缺点,如将50/60 Hz变为高频后经高频高压隔离变压器处理,这一问题就能得到解决。基于高频高压技术进行了EAST Snubber高压隔离偏置电源的设计与实验研究。 相似文献