Arc Flash Calculation of DC System in a Power Plant

The DC system provides power to control and emergency circuits of the power plant and high-voltage substations. The Arc flash calculation of the DC system is a significant concern for power plant operators who need to meet the requirements of the NERC and NESC guidelines. There are no IEEE or NESC standards for DC arc flash calculation that the utilities can follow to meet the mandatory requirements. This paper describes the DC arc flash analysis, existing calculation models, and arc flash methodology for 125V DC systems used in the power plant with a generation capacity of 500MW. The main objective was to evaluate DC arc flash conditions based on the existing equipment used in the system and to determine respective PPE categories. The results obtained using commercial software, whose calculation is based on the IEEE standard, are discussed. It will guide industry users on how to develop their DC systems design, maintain the safety of the workforce for their routine maintenance jobs, and fulfill the requirements of the federal and local regulatory agencies.