Study on the Closing Collision and Bouncing Characteristics of AMF Contact of Transmission Grade Vacuum Circuit Breaker

In the closing process of vacuum circuit breaker (VCB), the dynamic contact impact forces, which are significantly higher than the static contact forces, have a significant impact on the surface deformation of the contact and the strength of the vacuum arc extinguishing chamber and operating mechanism components. The objective of this paper is to study the the closing collision and bouncing characteristics of AMF contact of transmission grade vacuum circuit breaker. A model for simulation of the closing process of VCB was built. By simulation, the relative displacement curve of contacts was obtained. The influence of the closing velocity on stress distribution of key components of the contact and contact bouncing was analyzed. The results showed that the maximum value of closing bouncing was 1.16 mm and the total bouncing duration was 13.8 ms of this vacuum circuit breaker at closing velocity of 1.2 m/s. The peak stress of the steel nail was 360.57 MPa and the peak stress of the contact plate was 234.65 MPa. Both of them exceeded the allowable stress. The closing operation had the least damage to the structure of the contact at a closing velocity of 1.0 m/s. And the results also showed the influence of the closing velocity on the closing bouncing and the stress distribution of the contact.