Study of contact resistance in the design of a pyro-breaker applied in superconducting fusion facility

Pyro-breaker is a fast-responding and high-reliable explosive-driven circuit breaker, which has been applied in several quench protection systems, such as International Thermonuclear Experimental Reactor and Experimental Advanced Superconducting Tokamak. As an indispensable back-up switch, Pyro-breaker guarantees the reliability and safety of the system and avoids tremendous loss when quench happens. Electrical contact, a crucial part of an electrical device greatly determines the steady current capacity of a Pyro-breaker. However, due to the complexity of the model and the deficiency knowledge of the microstate of contact areas, an accurate calculation for contact resistance is difficult to acquire. A study of electrical contact in the design of a Pyro-breaker has been presented in this paper. An engineering calculation method is verified with experiments. Parameters are fitted for the presented model, which will be a significant theoretical basis for the future designing.