Experimental Study on Arcing Process of Vacuum Arc under Wan-Type Contacts

摘要

The arc characteristics which have a great impact on contact erosion play a decisive role on the interruption performance of vacuum circuit breakers. In this paper, a 3D model of wan-type contacts was built, the magnetic field distribution between the contacts and the electromagnetic force of the arc column were calculated. Then the experimental system was established. The characteristics of vacuum arc with different breaking currents from 4 kA (peak) to 13 kA (peak) were investigated. The arc appearance, variation of arc voltage and the duration of voltage noise were analyzed. Experimental results showed that as the peak current increased, the arc expanded more rapidly and had more constrictive appearance. The voltage noise occurred earlier and ended later as the peak current increased continuously. Meanwhile, the voltage noise was always accompanied by short-time constriction of arc or bright cores in the arc column. In addition, a special phenomenon with the arc root moving along the edge side of anode was observed when the peak current was more than 13 kA, leading to a melting speed of about 65 m/s, which was equivalent to the velocity of arc movement.