Solid-State Circuit Breakers for DC-Powered Buildings: An Overview of Standards, Directives, and Technologies

This paper presents a review of low-voltage direct current (LVDC) solid-state circuit breakers (SSCBs) for building power systems, focusing on relevant standards, safety directives, and design requirements for DC protection. A structured classification scheme is proposed for LVDC SSCBs based on key design criteria including the number of poles, bidirectional current capability, isolation method, semiconductor technology, and circuit topology. This paper also proposes a categorization of SSCB protective functions into elementary safety functions (short-circuit interruption, overcurrent and overload protection, and selective coordination) and additional advanced functions (arc-fault detection, insulation monitoring, and earth-fault protection), distinguishing fundamental requirements from enhanced safety features. Furthermore, a risk assessment framework grounded in ISO 12100 principles is introduced and tailored to LVDC installations employing SSCBs. This framework systematically identifies potential hazards and SSCB failure modes, guiding risk mitigation measures and the development of test procedures to ensure compliance with safety standards. Collectively, these contributions provide clear guidelines to support the safe integration, standardization, and future development of SSCBs in emerging DC power distribution networks.