Modeling and simulation of a 20kV ultra-fast DC circuit breaker for electric shipboard applications

A novel hybrid circuit breaker for medium voltage dc (MVDC) electric shipboard power systems is proposed. The breaker combines the benefits of the efficiency of a mechanical breaker and the interruption speed of a solid-state breaker. The proposed breaker utilizes a fast-ramping current source with a fast-actuating vacuum interrupter (VI) to provided ultra-fast response time and high on-state efficiency. During normal operation, nominal load current flows through the vacuum interrupter in the main conduction branch, providing a low-resistance path with negligible losses. During a fault, a current zero crossing is achieved by the use of a controllable resonant current source (RCS). By leveraging the high switching frequency capabilities of Silicon Carbide (SiC) devices, the current source achieves higher frequency of resonance than previously possible with the silicon counterparts. After interruption, the surge arrester in the energy absorption branch clamps overvoltages and dissipates all residual system energy. Simulation results from the PLECS software environment are presented to verify the functionality of this proposed breaker in a 20 kV MVDC system for electric shipboard applications.