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1、建立一个原型花费了大约16个月的时间，它的主要技术指标如表1所示。2、126KV真空断路器的结构126KV单断真空断路器的原型如图1所示。图中，三个真空灭弧室分别组装在各自的瓷套1上。瓷绝缘支座2安装在横向钢支架3上，三个永磁操作机构4分别安装在每个瓷绝缘支架2的末端，永磁操作机构4由控制箱5进行电控，从而实现同步开关。在横向钢支架3和钢基座7之间焊接有两个钢支撑6。真空断路器安装在水泥块上。相邻真空灭弧室之间的距离是1700mm，整个断路器的高度接近5000mm.3电极分析3.1、A型轴向磁场电极图2所示为A型轴向磁场电极的结构。如图3所示，在真空灭弧室中，当电流通过线圈时会产生一个磁场。在

2、峰值电流时，分布于接触体间隙的中间面的轴向磁通密度如图4所示，图中，在峰值电流平均值为40KA、接触体直径为100mm、接触面气隙为60mm时，中间面的最大轴向磁通密度为0.205T。合成电路测试表明，配有A型电极轴向磁场的真空灭弧室模型很好的中断了一个平均电流为40KA的短路电流。 3.2、B型轴向磁场电极图5所示为B型轴向磁场电极的结构。电流通过导引棒1流经线圈2，再进入接触圆板3，穿过圆板电流流经与之对应的圆板4、线圈5和棒6。当电流通过线圈2和线圈5时就产生了轴向磁场，峰值电流时，轴向磁场在接触气隙中间平面的分布如图6所示。图中，在峰值电流平均值为40KA、接触体直径为100mm、接触

3、面气隙为60mm时，中间面的最大轴向磁通密度为0.356T，这比A型轴向磁场电极时增加了74%。合成电路测试表明，配有B型电极轴向磁场的真空灭弧室模型很好的中断了一个平均电流为40KA的短路电流。3.3、C型轴向磁场电极图7所示为C型轴向磁场电极的机构，它是一个双极轴向磁场电极。如图8所示，电流经过导引轴，分成两路通过线圈，再流到一个连接圆盘，接着通过两个真空灭弧装置，此后，电流流经与之对应的连接盘，连个线圈以及导引轴。故而，在导引轴的两旁产生方向相反的感应磁场。在峰值电流平均值为40KA、接触体直径为100mm、接触面气隙为60mm时，中间面的最大轴向磁通密度为0.202T。4、硅油浇注技术

4、在高压真空断路器中，SF6是一种候选绝缘物质。考虑到其温室效应，我们采用Okubo和Yanabu的建议，尝试用硅油来替代作为126KV真空断路器的外部绝缘物质。硅油是一种透明的物质，它的浇注技术如下：1）先用蒸馏水清洗磁套内腔，再用100%的乙醇清洗。 2）如图9所示，将磁套内腔抽成真空。首先，打开真空阀将内腔压力抽到0.2Pa；其次，保持真空度在0.2-0.3Pa的同时打开硅油阀让硅油自由的流到内腔中直到达到指定的高度；第三，再次打开真空阀将油上的剩余空间抽成0.5Pa；最后，关闭真空阀打开N2控制阀，让N2将空间的压力充至1Pa。 3）24小时之后，观察N2压力计看N2压力是否正常从而判断

5、硅油浇注是否成功。5、关于额定电流的研究图1所示126KV真空断路器的的额定电流的有效值为1600A。为了提高它的有效电流，在断路器上安装了散热器，以提高它的额定电流水平。图10为本断路器的散热器的布局。如图11所示，为了提高126KV真空断路器的性能，在出口终端测出温升。测试结果表明，当额定电流的有效值为2000A时出口终端的温升为30K，这满足了中国的国家标准。当额定电流为2000*1.2=2400A时的额外温升测试结果表明，它既满足中国国家标准又满足ICE标准。这表明，借助于散热器技术额定电流由1600A增加到了2000A。6、大行程永磁操作机构的开发永磁操作机构的结构非常简单，它的组成

6、部件数仅为传统弹簧操作机构的25-40%。此外，它还具有高可靠性和长达100000次操作寿命等优点。永磁操作机构已经出现在市场上，使用于真空断路器后得到了很多的共同好处。我们开发了一种用于126KV真空断路器的大行程真空断路器，它的行程为60mm，平均分闸速度为3.5-4m/s。此外，永磁操作机构实现了同步操作，这进一步提高了高压真空断路器的性能。由于永磁操作机构的性能稳定，它可以用于控制分合闸时间为500us的真空断路器。当电流很低时，真空灭弧室很容易停止工作。根据我的经验，这将增加额定断路断开电压20-25%。在合闸操作时，冲击电流将减至0左右。7、结论本文介绍了中国首个126KV真空断路

7、器的设计特点，即：1）用硅油作为真空灭弧室的外部绝缘物质。2）增设了散热器，使真空断路器的额定电流增至2000A。3）利用永磁操作机构来实现同步开关操作。126 kV Vacuum Circuit Breaker Debuted in ChinaJimei Wang（Department of Electrical Engineering, Xian Jiaotong University Xian 710049, Shaanxi Province, P.R. China）Abstract- A single break 126 kV vacuum circuit breaker debute

8、d in China is introduced.Configuration of 126 kV vacuum circuit breaker and configuration of its electrode are illustrated. Particularly, silicone oil is used as external insulation of vacuum interrupters. Heat radiators are designed for raising rated current. Permanent magnet actuators with long st

9、roke are developed for improving performance of the vacuum circuit breaker.I. INTRODUCTIONA project of researching and developing 126 kVsingle break vacuum circuit breaker is being done by cooperation of Xian Jiaotong University, vacuum interrupter manufacturers and vacuum switchgear factories in Ch

10、ina. It took nearly sixteen months to finish a prototype. Its main technical objectives are shown in Table 1.II. CONFIGURATION OF 126 kV VACUUM CIRCUIT BREAKERThe 126 kV single break vacuum circuit breaker prototype is shown in Fig. 1, which shows three vacuum interrupters are individually assembled

11、 in each porcelain bushing 1. Porcelain insulating support 2 is mounted on a horizontal steel bracket 3, and three permanent magnet actuators 4 are separately installed at the end of each insulating porcelain insulating support 2, which are electronically controlled by control box 5, thus synchroniz

12、ation switching could be realized. Two steel vacuum interrupter that is assembled in porcelain bushing,2-porcelain insulation supporters, 3-horizontal steel bracket,4-permanent magnetic actuator, 5-control box, 6-steel supporting stand, 7-steel base supporting stands 6 are welded between horizontal

13、steel bracket 3 and steel base 7. The vacuum circuit breaker is fixed on a cement block. The distance between vacuum interrupters is 1700 mm and the total height of the breaker is approximately 5000 mm. III. ELECTRODE ANALYSISA. Axial magneticfield electrode-Type AConfiguration of type A axial magne

14、tic field （AMF） electrode is shown in Fig.2.J1 Magnetic field is generated with current passing through coils and it applies on vacuum arc, which is shown in Fig.3. The axial magnetic flux density distribution on intermediate plane of contact gap at current peak is shown in Fig.4. It showed that max

15、imum axial magnetic flux on the plane is 0.205 T at current peak with current 4OkA rms, contact diameter 100mm and contact gap 60mm. A synthetic circuit test showed that a vacuum interrupter prototype with the type A AMF electrode successfully interrupted a 4OkA rms short circuit current.B. Axial ma

16、gnetic field electrode-Type BFig.5 shows configuration of type B AMF electrode. 21 Current flows through conducting rod 1, then it goes one round in coil 2 and it enters contact 3. By passing through arc, current flows through counterpart contact 4, coil 5 and rod 6. AMF is generated with current pa

17、ssing through coil 2 and coil 5, and its distribution on intermediate plane of contact gap at current peak is shown in Fig. 6. The maximum axial magnetic flux density on the plane at current peak is 0.356 T with current 40 kA rms, contact diameter 100mm and contact gap 60mm, which is 7400 higher tha

18、n that of type A AMF electrode. Synthetic circuit test also proved that a vacuum interrupter prototype with type B electrode can successfully interrupt a 40 kA rms current.C. Axial magnetic electrode-Type CFig.7 shows configuration of type C AMF electrode 3.It is a bipolar AMF electrode. As shown in

19、 Fig. 8, current passes through a conducting arm, then it divides into 2 branches in a coil. After that current goes into contact plate and it passes through 2 vacuum arc columns. Thereafter it enters counterpart contact plate, 2 coil branches and conducting arm. So the induced magnetic field have o

20、pposite directions at 2 sides of conducting rods. The maximum axial magnetic flux density on intermediate plane of contact gap at current peak is 0.202 T with current 40 kA rms, contact diameter 100 mm and contact gap 60 mm.IV. SILICONE OIL POURING TECHNOLOGYSF6 is an external insulation candidate i

21、n high voltage vacuum circuit breaker. Considering its greenhouse effects, silicone oil was tried as an replacement of SF6 as external insulation of 126 kV vacuum circuit breaker, as suggested by Okubo and Yanabu. 41 Silicone oil is a kind of transparent liquids. Its pouring technology is as followi

22、ng:1） To clean porcelain bushing cavity with distilled water and then use 100 00 ethyl alcohol;2） To Vacuumize the porcelain bushing cavity as illustrated in Fig.9. First, open the vacuum valve to vacuumize the cavity to 0.2 Pa. Second, keep vacuum degree at 0.2-0.3 Pa and gradually open the silicon

23、e oil valve and let silicone oil freely flow in the cavity till reaching a specified height level, then close the vacuum valve. Third, reopen the vacuum valve to vacuumize the rest space over the oil to 0.5 Pa. Finally, close the vacuum valve and open the N2 gas valve to charge N2 into the space til

24、l to 1 Pa.3） The success of oil pouring technology can be examined by checking the N2 pressure at normal position or not with observing the gauge after 24 hours.V. RESEARCH ON RAISING RATED CURRENTRated current of 126 kV vacuum circuit breaker shown in Fig.1 is 1600 A rms. To raise its rated current

25、, heat radiators are installed on the breaker to improve its rated current level. Fig. 10 shows the layout of heat radiators attached to this breaker. Temperature rise was measured for the improved 126kV vacuum circuit breaker prototype at an outlet terminal, as shown in Fig. 11. Test results showed

26、 that temperature rise at the outlet terminal was 30 K with rated current 2000 A rms, which meets the requirements of Chinese standard. An additional test for temperature rise at rated current 2000 1.2=2400 A shows that it still satisfies the Chinese standard and IEC standard. This showed that rated

27、 current was increased from 1600A to 2000 A by the heat radiators technology.VI. DEVELOPMENT OF HIGH STROKE PERMANENT MAGNET ACTUATORConstruction of permanent magnet actuator is quite simple. Its parts number is only 25-40 00 of spring type actuator. Besides, it has merits of high reliable performan

28、ce and long mechanical life that is approximately 100,000 operations. Since permanent magnet actuator appeared on the market, it has drawn a common interest in vacuum circuit breakers. We developed a high stroke permanent magnet actuator for 126 kV vacuum circuit breaker. Its contact stroke is 60mm

29、and average opening velocity is 3.5-4 m/s. Moreover, synchronization switching can be realized by permanent magnet actuator that can further improve performance of high voltage vacuum circuit breaker. Because performance of permanent magnet actuator is stable, it can be used to control the contacts

30、of vacuumcircuit breaker, which open or close at about 500s prior to current zero. With much lower current vacuum arc is easy to extinguish. By my experience this may raise the rated short circuit breaking current by 20 -25%.And in closing operation, rush current can be reduced to nearly zero.VII. C

31、ONCLUSIONSDesign features of single break 126 kV vacuum circuit breaker debuted in China is introduced, which include:1） Silicon oil is used as external insulation of vacuum interrupters.2） Rated current of the vacuum circuit breaker was raised to 2000 A with heat radiators.3） Synchronization switching can be realized by permanent magnet actuator.