Expanded DC Arc Flash Model for 125V Substation Battery Backup Systems

Arc flash is one of two hazards primarily associated with electrical systems. Due to its prevalence, the majority of arc flash research has been dedicated to alternating current (AC) electrical systems. However, direct current (DC) electrical systems are becoming increasingly common, such as electrical storage systems (ESSs), solar photovoltaic (PV) panels, and high-voltage (HV) DC transmission lines. Thus, more research is needed to address the arc flash hazards posed by DC electrical systems. Current DC arc flash models are theoretical and lack empirical data compared with AC arc flash models. This paper presents models developed through empirical testing utilizing low-voltage (LV) station batteries. Furthermore, this paper investigates possible interactions between DC arc flash within LV battery systems and atmospheric conditions, such as temperature and relative humidity. Lastly, the paper provides information regarding the implementation of these models within American Electric Power's (AEP's) safety practices regarding batteries and DC panelboards.