Motion and Breakdown Related to Microparticles in Vacuum Gap
Motion and Breakdown Related to Microparticles in Vacuum Gap
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DOI：
10.1109/tps.2019.2925655
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发表时间：
2019-08
影响因子：
1.5
通讯作者：
H. Ejiri;A. Kumada;K. Hidaka;T. Donen;K. Kokura
中科院分区：
文献类型：
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作者：
H. Ejiri;A. Kumada;K. Hidaka;T. Donen;K. Kokura
真空断路器（VCBs）广泛应用于中压类断路器。在vcb中，电路电流中断后有时会发生晚期击穿，这些晚期击穿被认为是由微粒触发的。在直流电压作用下，观察了微粒子的运动和微粒子引发的击穿。事实证明，微粒的运动可以分为三种模式：附着在电极上，在电极上弹跳，在电极之间上下弹跳。尽管施加直流电压，但随着加速度的变化，一些微粒在飞行过程中获得了正/负电荷。微粒在阴极场发射电子轰击下产生二次电子发射带正电荷，同时吸收场发射电子带负电荷。根据微粒击穿前后的运动和发光的位置，微粒触发击穿的模式可分为六种模式。通过改变微粒尺寸，还测量了每种击穿模式的发生频率。可以说，为了防止间隙耐压性能的退化，应避免大而附着的微粒对间隙的污染。
Vacuum circuit breakers (VCBs) are widely used in the medium voltage class. In VCBs, late breakdowns sometimes occur after the circuit current has been interrupted, and these late breakdowns are thought to be triggered by microparticles. In this paper, the motion of the microparticles and the breakdown triggered by the microparticles are observed under the application of dc voltage. It turns out that the motion of microparticles can be grouped into three patterns: attaching to electrodes, bouncing at electrodes, and bouncing up and down between electrodes. Some microparticles gain positive/negative charge during the flight as the acceleration changes despite application of dc voltage. The microparticles are positively charged by the secondary electron emission under the bombardment of field emission electrons from the cathode, while they are negatively charged by absorbing field emission electrons. The patterns of breakdowns triggered by the microparticles can be grouped into six patterns according to the motion of the microparticles before/after the breakdown and the location of light emission. The occurrence frequencies of each breakdown pattern are also measured with changing the microparticle size. It can be said that contamination of the gap with big and attaching microparticles should be avoided in order to prevent degradation of the withstanding voltage of the gap.