This paper presents a novel ultrafast DC circuit breaker concept based on a railgun actuator, designed for ultrafast charging stations operating at 800V and delivering up to 640kW. The proposed breaker achieves contact opening speeds exceeding 190m/s, enabling fault current interruption within 200s and limiting the peak fault current to 2200A. This performance significantly reduces breaker stress compared with conventional mechanical solutions. System-level simulations demonstrate a dramatic reduction in energy dissipation during faults—from 11,000 J with a conventional fast breaker to just 250J using the proposed design. A 3D finite element method model of the railgun actuator confirms the feasibility of achieving a 15mm stroke in 150s. The evolution of current density and magnetic field is analyzed, highlighting the influence of skin and velocity skin effects. Results confirm that the proposed solution acts both as a circuit breaker and a fault current limiter, enhancing safety, reliability, and durability in high-power DC systems.
León et al. (Thu,) studied this question.