Observation of dynamic evolution process of vacuum arc microscopic particles based on emission spectrum principle

Abstract

The distribution of microscopic particles directly affect the recovery of post arc insulating medium and determine whether fault current can be interrupted. Based on the principle of vacuum arc emission spectrum, a high-speed spectrum observation platform was built to study the distribution of microscopic particles during the arc burning, and the axial and radial spectral line intensity and density distributions of atoms and ions under different current amplitudes were obtained. The results show that the CuI spectral line intensity has two peaks near the cathode and anode, while in the arc column it is relatively low. The peak of CuI spectral line intensity near the electrode is caused by electrode evaporation. The peak duration of CuI spectral line intensity near cathode is always longer than that near anode.CuII spectral line intensity is lower and appears later, disappears earlier, which in arc column increased obviously, compared with CuI. The CuII density near the cathode is higher than that near the anode, and the CuII density in the arc column is higher than two electrodes, which is similar to the axial distribution of electron density. The radial distribution curve of CuI and CuII density is similar to the radial distribution curve of spectral line intensity, showing the characteristics of high center and low edge in the radial direction of the arc gap. The difference is that the width of atomic spectral line is larger than that of corresponding ionic spectral line, the distribution curve of ionic spectral line is smooth and symmetrical, and the radial attenuation rate of CuII density is larger than that of corresponding CuI. This reflects the ionization of atoms and the effect of magnetic fields. The radial and axial distribution of particle density is opposite to that of excitation temperature. Electrode emission will first affect the atom formation.