Relationship between displacement characteristics of a 126kV vacuum circuit breaker and spring type operating mechanism

Spring type operating mechanism is widely used in high voltage circuit breakers. We investigated displacement characteristics of moving contact in opening and closing operation and how it is influenced by design of the spring type operating mechanism. Dynamics models were set up to demonstrate the relationship between displacement characteristics including initial opening speed, average opening speed, average closing speed and design parameters of operating mechanism including contact spring, over-travel, opening spring, cam and damper etc. Our simulation results show that the initial velocity increased significantly as over-travel and preload of contact spring increased. The damper and the cam can be designed to get a suitable displacement characteristic of movable contact.