Characteristic Analysis of Intermediate Frequency Vacuum Arc Based on Stereo Vision Technology

With the increasing demand of electric power for more-electric aircraft, current breaking and protection in intermediate frequency (360–800 Hz) AC power system becomes more and more difficult. Different from the case of power frequency at 50 Hz, the arc time is shortened due to the increase of current frequency, so that the anode spot is not significant when the intermediate frequency vacuum arc is generated. Therefore, a large number of metal droplets produced by contacts are important sources of metal vapor at post-arc stage, and the metal vapor will have a great influence on the recovery strength of dielectric. During the splashing process, the metal droplet continues to evaporate, and the Cu mass fraction on the surface of the droplet decreases from 65 to 10%. Stereo vision technology is used to calculate the velocity and acceleration of droplets sprayed by contacts in three-dimensional space, so as to obtain the pressure distribution in the intermediate frequency vacuum arc chamber during the process of post-arc breakdown. According to the parallax principle, the velocity of the droplets is about 10 m/s, and the acceleration is 105 m/s2, and the pressure gradient is 1.2 MPa/mm.