多棒极型触发真空开关的关键问题及应用研究

发布时间：2018-04-29 13:51

本文选题：MTVS + 电弧运动　；参考：《华中科技大学》2014年博士论文

【摘要】：多棒极型触发真空开关(Triggered Vacuum Switch with multi-rod electrode,简称MTVS)的电极结构由多对棒状电极相互交错排列形成多个间隙,实现了电弧的多通道发展,避免了电弧的集聚,从而具有转移库仑量高、通流能力强、工作电压范围宽,触发电压低、寿命长等优点。本文根据脉冲功率系统和配电网系统中的不同应用需求,从电弧运动机理、电极结构优化、极性效应、负极性触发特性以及大电流高库仑通流寿命等方面对MTVS进行研究,从而为此种开关的设计和推广提供理论依据和参考。建立了MTVS导通时的三维仿真模型,对在不同通流情况下其内部的纵向和横向磁场分布进行计算分析,同时还对不同导通情况下电弧弧柱以及棒状电极的受力情况及其影响因素进行了分析,仿真结果表明：在单个棒棒间隙导通时横向磁场占主导作用,而所有间隙导通时纵向磁场占主导地位,从而使得真空电弧能够在MTVS内部保持运动状态,这也是MTVS具有的高通流能力的本质原因；部分间隙导通时电弧通道和电极主要受到背向电极中心的径向电磁力,而所有间隙导通时则主要受指向电极中心的径向电磁力的作用。采用CMOS高速摄像机系统对MTVS中电弧的整体发展过程进行观测,并对电弧运动速率进行测量分析,研究发现在MTVS内的电弧运动速度最快可以达到1000m/s以上。在电流上升阶段真空电弧运动速度较快,且电弧亮度高；而在电流下降阶段电弧运动速度慢,且电弧光亮低,同时还出现了电弧停滞的现象。在电流峰值小于20kA时电弧只充满了部分间隙,当电流峰值大于20kA时电弧几乎充满MTVS所有间隙。采用有限元法对MTVS的静电场分布进行计算分析,并对其主电极结构进行优化设计,主要分析电极边缘的倒角半径等结构参数对其电场畸变系数的影响,计算结果表明当MTVS的顶端面倒角半径取5mm且棒极侧面边缘倒角半径取3mm时,可以使其电场畸变系数降低到最小值3。对MTVS的极性效应进行仿真研究,并对其在不同极性条件下的触发特性进行实验研究。研究表明MTVS的特殊结构决定了初始等离子体的扩散过程在正负极性配置下有很大的差别,因此MTVS具有较强的极性效应,当工作在正极性配置下时其触发可靠性高,触发时延及分散性小,然而在负极性配置下触发很困难,触发失败率较高。本文提出双MTVS反向并联的方式成功解决其在交流模式下的触发可靠性问题。最后对优化前后的MTVS样品的通流及寿命特性进行了实验研究,实验结果表明：(1)在电流峰值为100kA且脉宽为600μs单次转移电荷45C的条件下,MTVS的寿命大于1000次,且在通流100次之后其触发电压会达到一个稳定状态；而且MTVS的极限峰值电流为250kA,极限di/dt最高为9.1kA/μs；(2)在峰值为30kA脉宽为10ms单次库仑转移量为120C时寿命可以达到1000次以上,而且在通流200次之后其触发时延相对稳定在5μs左右,而触发电压也相对稳定在40-1000V范围内；在峰值电流为65kA且脉宽为22ms单次转移库仑量为402C的脉冲电流作用下,MTVS的寿命大于30次,触发时延在1-9μs范围内；(3)电极结构优化之后的MTVS的耐压特性有了明显提高,其最低平均直流击穿电压提高了62.8%；电极材料为铜铬合金的MTVS的最低平均直流击穿电压要比无氧铜MTVS的高出20%,且触发时延及分散性较小,触发电压相对较高。
[Abstract]:The electrode structure of Triggered Vacuum Switch with multi-rod electrode, abbreviated to MTVS, is arranged by multiple interlaced rod electrodes to form a number of gaps, realizing multi channel development of the arc and avoiding the agglomeration of the arc, thus having high transfer Coulomb, strong flow ability, wide working voltage range, and a wide range of working voltage. According to the different application requirements of the pulse power system and the distribution network system, this paper studies the MTVS from the arc movement mechanism, the electrode structure optimization, the polarity effect, the negative polarity triggering characteristic and the high current high coulomb flow life, so as to provide the theoretical basis for the design and popularization of this kind of switch. And reference.
The three-dimensional simulation model of MTVS conduction is established. The distribution of the longitudinal and lateral magnetic fields in the different flow conditions is calculated and analyzed. At the same time, the force situation and the influence factors of arc arc column and bar electrode are analyzed under different conduction conditions. The simulation results show that the transverse direction of a single bar rod clearance is transversal. The main role of the magnetic field is that the longitudinal magnetic field dominates all gaps, thus making the vacuum arc capable of maintaining the motion state within the MTVS, which is the essential reason for the high flux capacity of the MTVS; the arc channel and electrode are mainly radial electromagnetic forces at the center of the back electrode while the clearance is guided, and all gaps are in the gap. When conducting, it is mainly affected by the radial electromagnetic force of the center of the electrode.
The CMOS high-speed camera system is used to observe the overall development process of the arc in the MTVS, and the arc motion rate is measured and analyzed. It is found that the speed of the arc movement in the MTVS can reach the fastest speed above 1000m/s. In the stage of current rising, the velocity of the vacuum arc is faster and the arc brightness is high; and the electric current is in the stage of decreasing electric current. The arc velocity is slow and the arc light is low. At the same time, the arc stagnation appears. When the peak of current is less than 20kA, the arc is filled with only some gaps. When the peak current is greater than 20kA, the arc is almost full of all MTVS gaps.
The finite element method is used to calculate and analyze the distribution of the electrostatic field of MTVS, and the structure of the main electrode is optimized. The influence of the structure parameters and other structural parameters on the electric field distortion coefficient is mainly analyzed. The calculation results show that when the chamfering radius of the top end of MTVS is 5mm and the radius of the side edge chamfering radius of the rod is taken to take 3mm, it can be obtained. The coefficient of the distortion of the electric field is reduced to a minimum of 3.
The polarity effect of MTVS is simulated and the trigger characteristics are studied under different polarity conditions. The study shows that the special structure of MTVS determines that the diffusion process of the initial plasma is very different under the positive and negative polarity configuration. Therefore, MTVS has strong polarity effect when it works under the positive polarity configuration. The trigger reliability is high, the trigger delay and the dispersion are small. However, the trigger is very difficult in the negative configuration and the trigger failure rate is high. This paper proposes a double MTVS reverse parallel connection method to solve the trigger reliability problem in the communication mode successfully.
Finally, the flow and life characteristics of the MTVS samples before and after the optimization are experimentally studied. The experimental results show that (1) the lifetime of MTVS is more than 1000 times under the condition that the peak of current is 100kA and the pulse width is 600 u s single transfer charge, and the trigger voltage will reach a stable state after 100 times of flow, and the limit peak of MTVS. The value current is 250kA and the maximum di/dt is 9.1kA/ Mu s, and (2) the lifetime of the 30kA pulse width of 10ms single Coulomb transfer is 120C more than 1000 times, and the trigger delay is relatively stable at about 5 mu and the trigger voltage is relatively stable in the 40-1000V range after 200 times of flow, and the peak current is 65kA and pulse width. Under the action of pulse current of 22ms single transfer Coulomb of 402C, the life span of MTVS is greater than 30 times and the trigger delay is within the range of 1-9 s. (3) the voltage resistance characteristic of MTVS after the electrode structure optimization is obviously improved, the minimum average DC breakdown voltage is increased by 62.8%, and the electrode material is the minimum average direct current breakdown of the copper chromium alloy of the MTVS alloy. The voltage is 20% higher than that of the oxygen free copper MTVS, and the trigger delay and dispersion are small, and the trigger voltage is relatively high.

【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM564

【参考文献】