With the continuous improvement of current levels in power systems, the demands on the breaking capacity requirements of vacuum circuit breakers are getting higher and higher. The breaking capacity of vacuum breakers ...With the continuous improvement of current levels in power systems, the demands on the breaking capacity requirements of vacuum circuit breakers are getting higher and higher. The breaking capacity of vacuum breakers is determined by cathode spots, which provide electrons and metal vapor to maintain the arc. In this paper, experiments were carried out on two kinds of transverse magnetic field（TMF） contacts in a demountable vacuum chamber, the behavior of the cathode spots was recorded by a high-speed charge-coupled device（CCD） video camera, and the characteristics of the cathode spots were analyzed through the image processing method. The phenomenon of cathode spot groups and the star-shaped pattern of the spots were both discovered in the experiment. The experimental results show that with the condition of TMF contacts the initial expansion speed of cathode spots is influenced by some parameters, such as the tested current, contact gap, the structure of the contact, the contact diameter, the number of slots, etc. In addition, the influence of the magnetic field on the formation of the cathode spot groups, the distribution, and the dynamic characteristics of the cathode spots were analyzed. It is concluded that the characteristics of the cathode spots are due to the effect of the magnetic field on the near-cathode plasma. The study of the characteristics of cathode spots in this paper would be helpful in the exploration of the physical process of vacuum arcs, and would be of guiding significance in optimizing the design of vacuum circuit breakers.展开更多
The arcing process greatly affects the breaking ability after current zero.The instability stage is the transition stage from the ignition to the movement stage,which affects the arc movement characteristics.In this p...The arcing process greatly affects the breaking ability after current zero.The instability stage is the transition stage from the ignition to the movement stage,which affects the arc movement characteristics.In this paper,the arc characteristics during the instability stage on spiral-type contacts were investigated using a high-speed video camera.A multi-column parallel instability mode and a single-column instability mode were found during the instability stage.The arc appearance and constriction degree changed rapidly.The arc voltage usually increased accompanied by fluctuations.In addition,it was found that the current significantly influenced the arc mode and duration in the instability stage.With increased peak current,the probability of a single-column instability mode increased,and the fluctuation range and average time decreased.展开更多
基金supported by National Natural Science Foundation of China(No.51777153)
文摘With the continuous improvement of current levels in power systems, the demands on the breaking capacity requirements of vacuum circuit breakers are getting higher and higher. The breaking capacity of vacuum breakers is determined by cathode spots, which provide electrons and metal vapor to maintain the arc. In this paper, experiments were carried out on two kinds of transverse magnetic field（TMF） contacts in a demountable vacuum chamber, the behavior of the cathode spots was recorded by a high-speed charge-coupled device（CCD） video camera, and the characteristics of the cathode spots were analyzed through the image processing method. The phenomenon of cathode spot groups and the star-shaped pattern of the spots were both discovered in the experiment. The experimental results show that with the condition of TMF contacts the initial expansion speed of cathode spots is influenced by some parameters, such as the tested current, contact gap, the structure of the contact, the contact diameter, the number of slots, etc. In addition, the influence of the magnetic field on the formation of the cathode spot groups, the distribution, and the dynamic characteristics of the cathode spots were analyzed. It is concluded that the characteristics of the cathode spots are due to the effect of the magnetic field on the near-cathode plasma. The study of the characteristics of cathode spots in this paper would be helpful in the exploration of the physical process of vacuum arcs, and would be of guiding significance in optimizing the design of vacuum circuit breakers.
基金supported by National Natural Science Foundation of China(Grant No.51777153)
文摘The arcing process greatly affects the breaking ability after current zero.The instability stage is the transition stage from the ignition to the movement stage,which affects the arc movement characteristics.In this paper,the arc characteristics during the instability stage on spiral-type contacts were investigated using a high-speed video camera.A multi-column parallel instability mode and a single-column instability mode were found during the instability stage.The arc appearance and constriction degree changed rapidly.The arc voltage usually increased accompanied by fluctuations.In addition,it was found that the current significantly influenced the arc mode and duration in the instability stage.With increased peak current,the probability of a single-column instability mode increased,and the fluctuation range and average time decreased.
