Research on the action characteristics and breaking control of 100 kA series double break DC vacuum circuit breaker for CRAFT quench protection system

Abstract

The DC vacuum circuit breaker plays an important role in the quench protection system of the Comprehensive Research Facility for Fusion Technology (CRAFT) project. The study of the operating characteristics of vacuum circuit breakers can effectively improve breaking reliability. This article introduces the design and basis of the series double break DC vacuum circuit breaker for the CRAFT quench protection system. It adopts the electromagnetic repulsion driving method to ensure rapid action and the operating mechanism design to ensure the synchronization of the double break action. A magnetic shielding setting is proposed through simulation calculations to solve the uniformity of magnetic induction strength between breaks. Combining the test data of action characteristics with the theory of optimal opening distance for current zero crossing, a DC breaking platform for the vacuum circuit breaker was designed, and control strategies were determined, thus completing the 100 kA DC breaking experiment. The vacuum circuit breaker studied in this article meets the technical requirements of the CRAFT quench protection system and provides experience and experimental data for the design of high-current vacuum circuit breakers.