The Diagnosis of Metal Vapor Density After Arc Extinction By Plane Laser-Induced Fluorescence

The distribution of metal vapor is very important for the successful interruption of the arc, which directly affects the dielectric strength after the arc is extinguished. The purpose of this article is to observe the distribution of copper metal vapor after the arc when the arc is extinguished at different times by means of plane laser-induced fluorescence(PLIF). A voltage of 100V is applied to a 10mm gap, and a 45Hz sinusoidal current is generated by triggering the arc ignition, and its peak current is 2kA. A reverse current with a rising time of $\mathrm{30}\mu\mathrm{s}$ forces the sinusoidal current to extinguish at different times in its half cycle. The plane laser with a center wavelength of 324.8nm is used to excite the copper atoms, and ICCD camera is used to record the copper atoms distribution from the induced fluorescence. A pair of cup-shaped axial magnetic field (AMF) contacts made of CuCr50 were used in the experiment. The experiment found that when the arc was extinguished at 7ms, the copper vapor density value reache a peak, which is $1.8\times 10^{19} \mathrm{m}^{-3}$.