Experimental Study of Cathode Spots and Plasma Dynamic Characteristics Based on Electrode Grain Structure

CuCr alloy has the advantages of high mechanical strength and hardness, good electrical and thermal conductivity, high temperature oxidation resistance, abrasion resistance, etc., and is widely used in Vacuum circuit breaker. The distribution characteristics of cathode spots and plasma are two important objects to study the breaking mechanism of vacuum circuit breaker. To analyze the effect of electrode grain structure on the cathode spots and plasma, two kinds of electrodes with different Cr phase sizes were used to observe the cathode spots and plasma in this paper. The images of cathode spots and arc column plasma radiation intensity were recorded respectively, and the characteristic parameters of cathode spots and plasma distribution were obtained by matlab. The results show that the size of Cr phase decreases, the size of cathode spots decreases, the carrying current decreases, the quantity increases, and the diffusion velocity increases. It is helpful for the uniform distribution of cathode spots, current density on electrode surface and plasma in arc gap. The thermal diffusion rate of Cu phase is faster, and the cathode emission is more likely to occur first in Cu phase. The size of Cr phase decreases, the thermal process time is shortened, and the new cathode spots are generated faster.