Fabrication and Performance Evaluation of MOV for Voltage Clamping in SSCBs Using Simplified Test Equipment

The use of DC distribution networks increases with the increasing adoption of electric propulsion systems in ships. Conventional mechanical circuit breakers should be replaced with solid-state circuit breakers (SSCBs) capable of ultrafast interruption in the microsecond range to ensure protection for these networks. This study focuses on the development of a 1.1 kV 2 kA SSCB for protecting 10 MW-class electric propulsion ships. A voltage-clamping MOV, a semiconductor switching unit, which is the core component of the SSCB, and a simplified short-circuit test setup were designed and fabricated. The voltage-clamping performance of the MOV and the operational characteristics of the SSCB were analyzed. Results confirmed that the developed SSCB can perform high-speed DC power interruption under its rated capacity. The proposed SSCB could be applied to large-scale electric propulsion systems for ships and power trading systems based on high-capacity ESS DC distribution networks.