DC arc flash studies for solar photovoltaic systems, challenges and recommendations

A DC arc flash hazard exists in solar photovoltaic power systems but there is no widely accepted methodology for characterizing the severity of the hazard. Calculation methods have been proposed and most rely on the nameplate I-V characteristic of the PV modules at Standard Test Conditions to determine the worst case incident energy. This paper proposes to consider other factors in performing a DC arc flash hazard analysis including possible weather conditions and variations of PV module characteristics from the datasheet ratings. It is recommended to consider two conditions when determining the worst case incident energy from a PV system: (a) failure of all protective devices to trip within 2 seconds due to insufficient current, and (b) array output power exceeding the nameplate rating due to technological and environmental factors.