真空间隙与CO_2气体间隙串联开断大电流机理仿真研究

为提升采用CO_2气体作为灭弧介质的高压断路器大电流开断能力,对真空间隙与CO_2气体间隙串联开断过程进行研究。通过建立12 k V真空间隙与72.5 k V CO_2气体间隙组成的串联间隙电弧黑盒模型,分析两间隙承担暂态恢复电压起始时刻不同时两间隙协同作用关系;研究两间隙并联分压电容对间隙间电压分布特性的影响;对比串联间隙与单一气体间隙开断性能的差异。仿真结果表明:真空间隙先承担恢复电压有利于CO_2气体间隙介质强度快速恢复,真空间隙提前15~30μs承担恢复电压时串联间隙表现出较好的协同开断效果;两间隙在不同时刻承担恢复电压时设置合适的分压电容可优化间隙间的恢复电压分布特性。CO_2气体间隙串联真空间隙后可提升其大电流开断能力,为环保型高压断路器设计提供可借鉴方法。     

800k V63kA罐式SF6断路器的研制

目的：为了适应市场需求,需要设计开断短路电流63kA的800kV电压等级断路器。方法：以50kA断路器结构为基础,利用有限元分析技,模拟气流场等技术对灭弧室喷口,并联电容,分合闸特性等进行改进。结论：重新设计后LW56—800断路器通过了,各项型式试验验证。     

真空间隙与CO_2气体间隙串联的混合断路器电场仿真计算

利用真空间隙串联CO_2气体间隙组成混合断路器可补偿CO_2气体灭弧能力较差的缺点,使CO_2气体间隙获得接近SF6气体间隙的开断能力。为分析混合断路器各间隙的电位分布,搭建了5种不同布置方式的混合断路器模型,并利用ANSYS Workbench计算不同布置方式下混合断路器各间隙的电场分布。同时利用子模布型技术解决了模型计算量过大的问题,得到了不同布置方式下真空间隙与CO_2气体间隙的分压情况。分析仿真结果并综合考虑各因素,气体间隙在上且与真空间隙呈45°角的布置方式最为符合混合断路器的要求。最后,进行等效电容计算并分析了并联电容对各间隙分压的影响。仿真和计算结果可为混合断路器的结构设计提供参考与依据。     

固封极柱用真空灭弧室

固封极柱式真空断路器以其绝缘性能好、可靠性高、机械寿命长以及体积小等有点成为当代真空断路器的更新换代产品,因此对真空灭弧室的各项指标提出了更高的要求。该文从短路开断能力、绝缘水平、接触电阻和机械寿命等方面阐述了固封极柱用真空灭弧室的设计特点和生产工艺。     

220kV 线路断路器SF6泄漏引起220kV失灵保护动作的事故分析

SF6气体在断路器中主要起到绝缘、灭弧的作用,而且SF6必须在一定的密度下才能满足断路器的绝缘、灭弧的需要,当出现SF6气体泄漏时,为防止灭弧能力不足的断路器切断负荷或故障电流,会启动断路器的分闸闭锁继电器,使其串联在分闸回路上的辅助触点断开,从而达到闭锁断路器分闸的目的。然而当断路器的分闸闭锁信号出现时,线路保护范围内的故障无法通过线路断路器正常切除,从而使220kV失灵保护动作,引起故障的停电范围扩大。本文通过分析220kV线路断路器SF6泄漏引致220kV失灵保护动作的原理分析,针对事故的各种信号、现象进行分析,最终发现事故的原因并对故障进行处理。     

GIS在城网改造中的优势

SF6气体绝缘封闭金属开关设备（GIS），是城市电网建设和改装的重要设备，三相共箱，结构合理，性能稳定、安全可靠，绝缘性能好，具有优良的开断能力，连续开断额定短路电流20次无检修，盆式绝缘子采用真空浇注，表面光滑，抗尘埃污染能力高。     

Sf6断路器在冬季运行中容易出现的问题及解决方法

SF6断路器以SF6气体为绝缘灭弧介质,具有耐电强度高、灭弧能力强等特点,它在体积、重量、开断性能、载流能力、绝缘性能等方面都大大优于油断路器,介绍SF6断路器在冬季运行中容易出现的问题及解决方法,保障SF6断路器的安全运行.     

解析西门子SF6断路器AK14系列液压机构频繁打压的问题

1SF6矗压断路器的摄述随着电力逐渐走向市场,用户对供电可靠性的要求越来越高,因而促使SF6作为灭弧介质的SF6断路器在电网系统中的地位也越来越高．尤其在高压和超高压系统中应用尤为广泛。SF6断路器与以前的油断路器相比,最重要的一个优点就是灭弧机理的改进,正是由于采用了具有优良的灭弧能力和绝缘能力的SF6气体作为灭弧介质,因而具有开断能力强、动作快,体积小等优点,从而延长了断路器的使用寿命,减少了断路器在运行检修中的工作量。但也存在着金属消耗多,价格昂贵的缺点。随着电气设备状态检修的逐步开展,对SF6高压断路器的质量和性能要求越来越高,但SF6断路器仍旧是高压和超高压电器的重要发展方向。     

直流真空断路器换流参数LDW-PSO优化设计方法研究

直流真空断路器(DC VCB)被广泛应于直流输配电系统,但开断时需换流回路强制电流过零实现真空灭弧。换流回路参数直接影响主断路器灭弧能力、弧后鞘层发展速度以及断路器设计成本。本文以有源直流真空断路器为研究对象,结合连续过渡模型建立开断过程各阶段状态方程。考虑多约束条件构建灭弧能力强、弧后鞘层发展速度快和断路器设计成本低的适应度函数;利用权重线性下降PSO算法(LDW-PSO)获得各优化目标下换流电感L和换流电容C参数配置。综合考虑各目标优化配置结果构建最佳适应度函数,并利用LDW-PSO优化得到12 kV/10 kA有源DC VCB的换流参数LC的最佳配置。仿真结果表明,该方法确定的LC参数在确保断路器可靠关断的同时可有效降低断路器的设计成本,达到优化设计目的。     

塑壳断路器中灭弧室的优化设计与试验研究

为了提高塑壳断路器的分断能力,对其灭弧室进行优化设计。基于电弧开断过程的理论研究,提出提高电弧电压的3种方式:1)优化灭弧栅片的结构,采用第1片引导、最后一片阻隔加上中间正常排布的方式,实现良好的切割电弧的效果;2)增加电机槽的磁吹结构,通过提高电弧受到的磁吹磁场强度来加快电弧的运动速度,借助ANSYS仿真方法可得新增加的磁吹结构使电弧增加了97N的磁吹力;3)增加气吹结构,利用降低弧柱的温度来提高弧柱压降,采用介质恢复强度快的产气材料PA66作为气吹片。组合使用得到优化后的设计方案并制作样机,在室温(25℃)及415V交流电压条件下进行短路分断实验,其分断能力由50kA提升至70kA,同时燃弧时间由5ms缩短至3ms。实验后拆解样机发现有部分试品出现灭弧室外壳破裂的问题,则将栅片基座开裂位置的壁厚增加2mm,借助ANSYS的静力分析模块,对变更前后的外壳进行等效应力比较,分析结果显示新结构的强度提升了40.2%,再次装配样机后,最终顺利通过工程试验。研究成果对后续塑壳断路器的新品开发及改进设计具有一定的参考作用。     

Development of a superconducting fault current limiter using various high-speed circuit breakers

The authors constructed and tested a model superconducting fault current limiter (SFCL) using a high-temperature superconducting film according to a design that includes a vacuum interrupter with an electromagnetic repulsion mechanism. The superconductor and the vacuum interrupter are connected in parallel with a bypass coil. If a fault occurs and current flows through the system, the superconductor is quenched and the current is transferred to the parallel coil because of the voltage drop in the superconductor. This large current in the parallel coil actuates the magnetic repulsion mechanism of the vacuum interrupter. On opening the vacuum interrupter, the current in the superconductor is interrupted. This model is expected to exhibit very low-energy consumption by the superconductor. The authors succeeded in interrupting the current flowing in the superconductor within a half-cycle using a prototype SFCL. An improved SFCL with higher voltage and current ranges was used to carry out current-limiting tests and to investigate the possibility of adapting our SFCL in a power system. The authors also carried out a currentlimiting test using a conventional high-speed vacuum circuit breaker (HSVCB) as a new method for realising our concept.     

真空断路器真空度与灭弧室屏蔽罩上感应电位联系机理研究

屏蔽罩电位是判断真空断路器灭弧室真空度水平优劣的一种技术手段,研究人员对屏蔽罩电位信号成分及其形成机理进行了大量的研究工作,并在理论上和试验方面取得了一定成果。但对于真空屏蔽罩上电位的成因并无公认的解释,且实际应用中难以将不同型号的断路器按同一标准对待。为寻求真空度与屏蔽罩电位的内在联系机理,本文基于前人研究成果,从电介质学及气体放电的相关理论出发,将真空度劣化过程分成三个阶段分别讨论,阐述了各个阶段依据理论基础。特别针对真空度高于0.1 Pa时较难判断的屏蔽罩电位值,利用有限元分析的方法进行了3D电场计算,分析了该真空度范围下屏蔽罩电位的变化规律,研究成果提供了一种真空度判断与评估的可行方法,具有较好的应用参考价值。     

Design of Power Supplies for the Pulsed High Magnetic Field Facility at HUST

Two types of pulsed power supply, a modular 12 MJ/25 kV capacitor bank and a 100 MVA flywheel pulsed generator, are under construction for the pulsed high magnetic field facility at the Huazhong University of Science and Technology (HUST) in Wuhan, China. The capacitor bank consists of 11 independent 1 MJ modules with a short circuit current of 40 kA each and 2 independent 0.5 MJ modules for 50 kA each. The bank is used to energize coils for magnetic fields in the 50–80 T range with pulse duration from 15 to 200 ms. The pulsed flywheel-alternator is used to energize a 50 T/100 ms long-pulse magnet via two 12-pulse power converter modules. Each converter module is designed to operate in the 95 to 66 Hz frequency operation range of the generator and can provide a no-load voltage of 4.6 kV and a full-load voltage of 3.4 kV at the rated current of 20 kA. In this paper the design of these two types of power supply is presented.     

双断口真空开关的动态介质恢复特性分析

从双断口真空开关的等值模型出发,分析了双断口真空开关的动态介质恢复过程,说明只要恢复电压的峰值和上升速度低于某一极限值,整个双断口真空开关并不会因为一个灭弧室发生重击穿而导致开断失败。这是因为另一个真空灭弧室的介质强度仍可能高于此时的恢复电压,它还可以承受整个恢复电压一个比较短的时间,当重击穿的真空灭弧室的介质恢复以后,共同完成分断过程。仿真计算和试验结果表明,由于各真空灭弧室断口的恢复电压分布不均匀,使得各灭弧室弧后电荷鞘层的发展不同,进而影响了各自的实际介质恢复特性。这可以解释双断口及多断口真空开关与单断口真空开关相比开断能力有显著提高的机理。     

Characterization of the high current triggered vacuum switch

The triggered vacuum switch (TVS) is widely used in the electromagnetic launcher (EML) system. An important performance of TVS with the six-gap rod electrode system which has been used in experimental research is long operating life, the high current and high coulomb. A major feature of TVS is capacity of carrying high current. Therefore, this paper focuses on the main current characteristics of the TVS. The result shows that under the capacitance of 1200 μF, the experiment was repeated 300 times when the current flowing through TVS was 100 kA, the characteristic of TVS is not damaged, the trigger voltage is maintained at 4-5 kV, insulation resistance is 2000 MΩ. In another case, when the capacitor value is 4400 μF, the current flowing through TVS was 207 kA, it can be repeated several times, until TVS is damaged, insulation resistance drops to 0 Ω. The result proves that the surface flashover triggered vacuum switch of a six-gap rod electrode can withstand 200 kA current, the transfer charge is 75 C.     

Dielectric characteristics of vacuum circuit breakers with CuCr and CuBi contacts before and after short-circuit breaking operations

This paper presents the results of the degree of irreversible changes of dielectric properties of vacuum circuit breakers with CuCr and CuBi contacts before and after short-circuit breaking operations. Tests of dielectric properties were performed on four different types of switching vacuum chamber with RMF electrodes in the form of a spiral disk with slots. The paper describes the configuration of measuring system for determining the dielectric properties of circuit breakers with DC, AC and pulse voltage. It also describes the measuring procedure. The results were analyzed and the experimentally obtained random variable breakdown voltage is found to belong to Weibull distribution in all cases. Based on these results it was found that for the vacuum circuit breakers with CuCr contacts and CuBi breakdown occurs by the emission mechanism after stopping of diffuse arc with the initial breakdown at the anode. It was also found that significant reduction of the breakdown voltage occurs only after a short-circuit current breaking for a constricted arc. Only in this case, the significant difference between circuit breakers with CuBi and CuCr contacts is observed. This difference is explained by the fact that breakdown voltage for a constricted arc strongly depends on the shape of the applied voltage by the action mechanism of micro particles generated during the breaking of the arc current for the vacuum circuit breakers with CuBi contacts and it is caused by material of contacts. The results confirm the lower degree of irreversible changes of dielectric properties of vacuum circuit breakers with CuCr contacts in operation.     

Dielectric characteristics of vacuum circuit breakers with CuCr and CuBi contacts before and after short-circuit breaking operations

This paper presents the results of the degree of irreversible changes of dielectric properties of vacuum circuit breakers with CuCr and CuBi contacts before and after short-circuit breaking operations. Tests of dielectric properties were performed on four different types of switching vacuum chamber with RMF electrodes in the form of a spiral disk with slots. The paper describes the configuration of measuring system for determining the dielectric properties of circuit breakers with DC, AC and pulse voltage. It also describes the measuring procedure. The results were analyzed and the experimentally obtained random variable breakdown voltage is found to belong to Weibull distribution in all cases. Based on these results it was found that for the vacuum circuit breakers with CuCr contacts and CuBi breakdown occurs by the emission mechanism after stopping of diffuse arc with the initial breakdown at the anode. It was also found that significant reduction of the breakdown voltage occurs only after a short-circuit current breaking for a constricted arc. Only in this case, the significant difference between circuit breakers with CuBi and CuCr contacts is observed. This difference is explained by the fact that breakdown voltage for a constricted arc strongly depends on the shape of the applied voltage by the action mechanism of micro particles generated during the breaking of the arc current for the vacuum circuit breakers with CuBi contacts and it is caused by material of contacts. The results confirm the lower degree of irreversible changes of dielectric properties of vacuum circuit breakers with CuCr contacts in operation.     

14 kV single-phase superconducting fault current limiter based on YBCO films

We present the fabrication and short circuit test results of a 14 kV single-phase resistive superconducting fault current limiter (SFCL) based on YBa₂Cu₃O₇ (YBCO) films. Individual components were processed using the 4″ YBCO films and have the rated voltage and current of 600 V and 35 A at 77 K, respectively. Twenty four components, eight components in series and three lines in parallel, make a module having the rated voltage and current of 4.8 kV and 105 A, respectively. Three modules were assembled in series to produce the SFCL working at 77 K, a 14 kV single-phase machine for the 22.9 kV Y-Y grid. short circuit tests were successfully conducted in an accredited test facility with the maximum fault currents up to 14.1 kA_P. All components quenched together upon faults and shared the rated voltage evenly without any supplementary device between the modules. This proves that the SFCL based on YBCO films may not only work reliably at 22.9 kV, but also provide technical feasibility for higher voltage application including the transmission grids.     

基于图像序列短间隙真空开关电弧形态研究

研究短间隙真空开关电弧扩散运动特性对促进真空开关向高电压等级、大容量及智能化发展具有重要的意义。本文利用高速摄像机CMOS对真空开关电弧图像进行了采集并获得了序列电弧图像;分析了真空电弧燃烧过程扩散运动的机理及特征。综合数字图像处理技术,提出了基于二值背景差分法电弧图像燃烧扩散运动识别算法。实验结果表明:运用图像系列背景差分法可实现对真空开关电弧图像面积扩散区域进行检测,且通过计算可得到真空开关电弧在燃烧过程中不同时刻的扩散速度。