During the operation of a fusion device, plasma instability can trigger various electromagnetic interferences and thermal radiation, potentially leading to a quench. A quench protection system is crucial to ensure stable plasma confinement and the safe operation of the entire device. Given the extreme requirements for vacuum circuit breaker (VCB) in fusion applications—such as interrupting super-large currents and withstanding harsh electromagnetic and thermal environments—traditional operating mechanism designs may not be directly applicable. To meet the rapidity and reliability demands of the operating mechanism, this paper conducts a kinematic and dynamic analysis of the VCB. By integrating the characteristics of large-capacity vacuum interrupters and electromagnetic repulsion mechanisms, the optimal transmission ratio of the indirect-acting VCB is derived. Through comparisons of initial acceleration, it is validated that indirect-acting operating mechanisms are more suitable for fusion device VCBs. Dynamic tests were performed on the developed prototype. The experimental results show that the operating mechanism designed with the optimal transmission ratio achieves the required opening time for fusion devices. Meanwhile, the high consistency of mechanical actions during repeated operations demonstrates stable and reliable breaking performance. This work provides a theoretical foundation and technical reference for the design of high-current DC VCBs in extreme environments.
This paper presents the design and testing of a high-current vacuum circuit breaker (VCB) operating mechanism for fusion devices. The mechanism is designed to rapidly interrupt large currents and withstand harsh electromagnetic and thermal environments during plasma quench events. The authors analyze the kinematics and dynamics of the VCB, optimize the transmission ratio, and validate the performance through dynamic testing.