低压直流断路器的限流技术

本文作者首先回顾了在低压直流断路器中使用的几种限流技术,然后,介绍了电力电子器件与低压直流断路器的结合,最后,对进一步研究限流技术提出了展望     

Comparing test requirements for low-voltage circuit breakers

Low-voltage circuit protective devices include low-voltage power circuit breakers, insulated case circuit breakers, and molded case circuit breakers. Each of these circuit breaker types is used for particular applications, and is tested against standards that relate to those applications. In North America, low-voltage power circuit breakers are designed and tested in accordance with ANSI/UL standard 1066, which in turn refers to the series of applicable ANSI C37 standards. Insulated case circuit breakers and molded case circuit breakers are designed and tested in accordance with the UL standard 489. In this paper the standards are compared by means of tables. The standards for low-voltage power circuit breaker and the molded case circuit breaker have many common elements. As a consequence, either type of circuit breaker could be used for some applications. However, there are several significant performance differences that relate to the application of these circuit breakers. Specifically, the low-voltage power circuit breaker is normally applied upstream of the molded case circuit breakers     

低压直流断路器的设计和使用

根据直流电弧灭弧理论方法,分析了低压直流断路器的主要设计要点,包括多断口串联、触头导电系统、灭弧室、磁吹和气吹灭弧的设计.最后介绍了低压直流断路器的使用要求.     

小型断路器限流技术

小型断路器广泛地用于终端供电线路中,其中一个关键技术是断路器限流技术的应用.分析了限制短路电流的条件,介绍了目前小型断路器采用的限流技术,如U形触头系统、气吹灭弧和变电弧电阻熄弧等概念.     

有源配电网中的断路器应用研究

为解决有源网络的保护问题,对相关的断路器应用技术进行了研究。通过对电弧更有效的控制,实现直流断路器的开断能力与极性无关,使其满足光伏发电系统的保护需求。通过将真空灭弧技术与ACB操作机构相结合,提高断路器在AC690~1 140 V电压下的开断能力。通过对操作过程的有限元分析和优化设计,提高断路器的操作寿命,使其满足风力发电系统的保护需求。通过采用方向性的区域选择性联锁技术,解决了多电源系统中的选择性保护问题。运行经验表明,上述工作有效提高了有源网络运行的安全性。     

低压断路器中空气电弧重击穿现象的仿真与实验研究

低压断路器用于接通和分断电路中的电流。当故障电流产生时，动触头和静触头打开，在触头间产生电弧，随后在电磁场和气流场的作用下向灭弧栅片运动。在运动过程中会出现电弧的停滞和后退的重击穿现象，严重降低了断路器的开断性能。该文以磁流体动力学(MHD)为基础建立了三维空气电弧等离子体在外部磁场作用下运动的数学模型，此模型可以预测电弧的重击穿现象，并发现当灭弧室的出口面积为60%时，电弧在3mT磁场的作用下运动时出现了重击穿现象，而当磁场增大到5mT时重击穿现象消失。此外，还发现当磁场为10mT时，在出口面积分别为20%、60%和100% 3种情况下电弧均可以顺利到达栅片，在运动的过程中没有电弧重击穿现象的发生。     

舰船电力系统新型限流保护技术的仿真分析

针对舰船直流电力系统极限短路电流难以分断的问题,开展了舰船电力系统新型混合式限流保护技术的仿真分析.通过建立含限流断路器的电力系统仿真模型,分析了舰船电力系统安装直流限流断路器的限流效果.仿真结果表明,新型限流断路器能够满足舰船电网对保护设备快速性和有效性的要求.     

Extending the Application Field of Vacuum Circuit Breakers to Generators for Capacities up to 400 MW

The progress that has been achieved in the development and manufacture of vacuum circuit breakers opens the possibility of using them for a wider range of applications at power plants, including as generator circuit breakers. Such characteristics of modern vacuum circuit breakers as increased breaking capacity and high switching life are factors that make them closer in competitiveness to SF6 circuit breakers for generators with capacities up to 400 MW. The article considers problem aspects relating to clearing of short-circuit faults in the generator voltage circuits and interruption of out-of-phase making currents and no-load currents of generator transformers. Conditions leading to a longer period of time to the moment at which the switched current crosses zero are considered. It is pointed out that, unlike the IEC/IEEE Standard 62271-37-013, GOST (State Standard) R 52565-2006 does not specify the requirements for generator circuit breakers in full. The article gives the voltage drop values across the arc for different design versions of vacuum circuit breaker contacts and shows the effect the arc in a vacuum circuit breaker has on the time delay to the moment at which the current crosses zero. The standardized parameters of transient recovery voltage across the generator circuit breaker contacts are estimated along with the contact gap electric strength recovery rates ensured by modern arc quenching chambers. The switching overvoltages arising when vacuum circuit breakers interrupt short-circuit currents and no-load currents of generator transformers are analyzed. The article considers the most probable factors causing the occurrence of switching overvoltages, including current chopping, repeated breakdowns of the circuit breaker contact gap, and virtual current chopping. It is found that, unlike repeated breakdowns and virtual current chopping, an actual current chopping does not give rise to dangerous switching overvoltages. The article also determines the vacuum circuit breaker application field boundaries in which dangerous switching overvoltages may occur that would require additional measures for limiting them.     

自适应限流型固态断路器的直流电源设计

为消除常规限流电抗对直流系统运行稳定性和直流断路器断流速度的不利影响,桥式限流型固态断路器实现了兼具自适应故障限流与断流的优异性能,但其桥电路中的直流偏置电源存在无过流保护和电源容量与投资成本相对较高的缺陷。针对桥式限流型固态断路器,文中设计了一种基于三相半波整流电路的直流偏置电源,提出了偏置电源参数选取和电压整定方法,有效减少了电力电子器件数量,实现了偏置电源过流保护电路,降低了偏置电源设计容量和制造成本。样机实验和仿真算例证明了所提出的自适应限流型固态断路器的偏置电源的优势。     

Comparing direct and synthetic tests for interruption ofline-charging capacitive current

Using a validated arc model, this paper analyzes current distortion and voltage waveforms during both direct and synthetic tests for interruption of line-charging capacitive current by power circuit breakers. Although the voltage of the electric arc drawn between breaker contacts may produce significant current distortion, it is demonstrated that the most significant parameter affecting the breaking capacity of power circuit breakers in capacitive-current switching tests is the voltage jump appearing across breaker contacts immediately after current interruption. It is essential to correctly define the supply circuit impedances and the associated voltage jump so as not to reduce or increase this test severity unduly     

低压断路器结构设计的发展动向

介绍了几种结构新颖的低压断路器。包括旋转动作的断路器、封闭式万能断路器和低压真空断路器，以这些最新开发的电器为基础，论述了低压断路器结构设计的发展动向。     

Summary of IEEE Guide for the Protection of Network Transformers

A summary is given of C37.108-198X, a new IEEE Guide. The summary describes the equipment used in a typical network transformer system. The performance of this equipment is described during fault and nonfault system conditions. The limitations of the present protection are addressed, most importantly, for low-voltage, low-current arcing faults. Protective devices that can be added to the existing network transformer protection are listed. Some of these devices sense conventional input quantities such as phase current, ground current, impedance, and transformer rate-of-pressure rise, whereas others sense heat, ultraviolet light, and smoke. The application of interrupting devices such as circuit breakers, vacuum interrupters, fuses, and current-limiting fuses including an electronic fuse are discussed with special application considerations identified. An example demonstrating how a protective system can be designed utilizing the devices described within the guide is included as an appendix to the guide     

高压开关设备的状态维修技术

金属开关柜柜内和手车触头温升、断路器机械特性及断路器触头电弧烧损是造成开关柜设备故障的重要原因,对它们进行有效的实时监测是实现开关设备维护方式转换的关键。介绍了CG2061型高压断路器触头温升在线测量系统原理及应用,永磁操动机构断路器远方监视技术及断路器触头电弧烧损监测技术。分析了断路器分闸动作时线圈电流波形与动铁心位移关系。列举了断路器短路开断电流与开断次数的计算方法。指出了将运行成熟的在线监测技术纳入设计和制造中,可以降低电器产品在线监测单元的安装费用,减少不必要工作。     

基于抑制起弧原理的中压无弧直流断路器

直流断路器是多端直流输电和直流配电网的关键设备。机械式和混合式直流断路器面临的困难是开断过程中触头间存在燃弧问题。文中讨论了产生电弧的电场强度和电压条件,并通过大量实验统计分析,总结出了抑制起弧所需满足的电场强度和电压条件。设计了抑制起弧的辅助缓冲电路,用以限制开断过程中触头间电压的上升,使其低于由机械开关速度决定的触头间介质绝缘电压,从而实现了直流断路器的无弧开断。通过仿真和低压模拟实验验证了抑制起弧原理和缓冲电路设计的正确性和有效性,并分析了中压无弧直流断路器的可行性。     

论低压断路器的性能和应用

介绍了低压断路器的分类、结构、常见类型、特性，及在不同场合中对断路器的选择，阐述了断路器在配电线路和电动机的保护中的应用。     

国外新一代塑壳断路器的现状和发展动向

介绍了近年来国外著名电气公司开发的新一代塑壳断路器(如双断点触头系统、电子脱扣器、可通信断路器、接地故障保护和剩余电流保护等)及其技术指标、产品结构特点和技术发展方向,对国外塑壳断路器的发展进行了全面的阐述。     

The effect of DC offset on instantaneous operating characteristicsof low-voltage circuit breakers

This paper addresses the effect of asymmetrical currents on factory adjustments and field verification of low-voltage circuit breaker instantaneous trip units. Both molded case circuit breakers (MCCBs) and power circuit breakers are pertinent. Factory adjustment of low-voltage circuit breakers, based on test results using asymmetrical current, may cause the circuit breaker instantaneous unit to perform improperly and result in inadequate protection and coordination of electrical system apparatus. Similarly, field testing conducted to verify proper performance of low-voltage circuit breakers, using asymmetrical current, may lead to the erroneous conclusion that the circuit breaker's instantaneous unit is out of specification. In addition to addressing the difficulties presented by this phenomenon, this paper also proposes an approach to identifying and overcoming these testing difficulties     

无弧直流快速断路器及关键技术研究

无弧直流快速断路器主要由真空灭弧室、高速稳定操动机构、智能控制器构成,具有环保高效、安全可靠的优点。对直流断路器的熄弧原理、直流断路器发展、无弧直流快速断路器的关键技术进行研究。     

Transient recovery voltage requirements associated with the application of current-limiting series reactors

This paper describes transient recovery voltage (TRV) requirements for switching devices used in the application of current-limiting series reactors. For fault current-limiting reactors, the series reactor is used during high fault current conditions. During these conditions, the line breaker is required to interrupt faults that may occur on the line-side of the reactor. For load current-limiting reactors, the series reactor bypass switch is normally closed and is opened to insert the reactor if the load current exceeds the line ampacity. For this situation, the bypass switch must interrupt the load current as it transfers from the switch to the series reactor. The study approach and modeling techniques described in this paper examine TRV requirements for circuit breakers and bypass switches to address (a) TRVs exceeding the rating of the line breaker following the interruption of a fault current, and (b) TRVs exceeding the bypass switch capabilities during reactor insertion. The study results are compared to ANSI/IEEE TRV Standards and corrective actions recommended, including control of series reactor natural frequencies. Effects of variations in the series reactor impedance, variations in bus-fault duty, and impacts of wave-traps and current chopping on TRV are described in the investigation. The results of the study provide guidance for the application of line breakers and bypass switches associated with the installation of current-limiting series reactors.     

IGBT串联均衡控制方法及其高压直流装备应用可行性研究

大功率电力电子技术一般通过器件或模块串联实现高电压耐受,在常规高压直流和早期柔性直流输电换流器中,采用了晶闸管或IGBT直接串联技术。而基于模块级联的换流器技术因具备高扩展能力,成为目前柔性直流输电主流路线,同样也应用于高压直流断路器等设备中。首先,对IGBT器件直接串联的技术进行探讨;然后,分析串联IGBT开关组件在柔性直流输电、高压直流断路器等场合应用的方式,提出对应的设计方案;最后,对设计方案进行分析计算。研究结果表明,在现有的基于级联模块的高压直流断路器设备中,通过采用IGBT直接串联组件,可以有效地降低其体积和成本,但对于柔性直流换流器,该方案没有显著的提升效果。