Design and safety-oriented development of high-voltage testing of solid-state circuit breakers for all DC marine applications

The increasing adoption of medium-voltage direct-current (MVDC) distribution systems in marine vessels demands fast, reliable, and experimentally validated fault protection technologies. Solid-state circuit breakers (SSCBs) have emerged as a promising solution due to their microsecond-scale interruption capability. However, validating SSCB performance at MVDC levels requires a controlled laboratory environment capable of safe highvoltage operation, galvanic isolation, fault-energy management, and transient capture. This paper presents the complete development, design considerations, and testing methodology for a 3 kV MVDC SSCB experimental test rig intended for short-circuit and transient-interruption studies. The high-voltage subsystem comprises a 3 kV Film capacitor bank, a charging interface, a discharge network, and a fault emulation and clearing mechanism. It is described along with the automated central controller that enables fully isolated, human-free execution of short-circuit tests. An isolation design framework is proposed to ensure safe oscilloscopebased measurements. A stepwise testing methodology is outlined, enabling gradual voltage escalation with continuous verification of electrical and isolation constraints. Experimental safety is further reinforced through a comprehensive MVDC risk assessment covering hazards such as electrocution, device failure, enclosure energisation, and arcs/fire. The resulting test platform provides a reliable and repeatable environment for evaluating MVDC SSCB technologies and supports future research into advanced fault protection, gate-drive coordination, and transient voltage suppression techniques.