Diagnosis of the power frequency vacuum arc shape based on 2D-PIV

Abstract

Abstract Vacuumcircuit breaker (VCB) is one of the important elements in the power grid that can control and protect the system. The diagnosis of the vacuum arc images in VCBs is helpful to the study on their breaking performance. But up to now, there are few reports on the macro-particle motion trajectories in the arc. As the macro-particles in the arc are flowing, the particle image velocimetry (PIV) can be grafted into the vacuum arc image processing. In this paper, the power frequency vacuum arc (peak is 6.9kA) was used as the treatment object, geometric characteristics of the vacuum arc shape using digital image processing technology were extracted, and the two dimensional motion trajectory and velocity distribution of the arc macro particles in different arc combustion stages were obtained based on 2D-PIV technology. Three stages were analyzed. In the rapid diffusion stage, the collision of the macro-particles is very intense in the anode region, and they spray along the anode surface. In the stable combustion stage, the velocity of the particles near the anode is small, and there is a smaller shrink. And finally in the extinction stage, their motion trajectories are in a state of rotation, near the anode and cathode are in a state of contraction.