Abstract: This paper presents a detailed study on relay coordination and arc flash hazard analysis for a 27-bus industrial electrical network using ETAP. In complex industrial systems, ensuring proper coordination between protective devices and minimizing arc flash risks are critical for both system reliability and personnel safety. The work begins with modelling the network and performing short-circuit analysis to determine fault levels at various buses. Based on these results, overcurrent relay settings are calculated for different protection stages, including both phase and ground faults, using definite minimum time (DMT) and inverse definite minimum time (IDMT) characteristics. Time-current coordination (TCC) curves are then developed to verify the selectivity and proper sequence of operation between upstream and downstream devices, including low-voltage breakers. The coordination process ensures that faults are cleared by the nearest protective device without unnecessary tripping of the entire system. Following this, an arc flash study is carried out to evaluate key parameters such as arc flash boundary (AFB), fault clearing time (FCT), incident energy, and working distance. The analysis helps in identifying critical sections of the network where higher incident energy levels pose safety concerns. It is observed that fault clearing time and relay coordination significantly influence arc flash severity. Based on the results, arc flash labels are generated to provide practical safety information for field implementation. Overall, the study demonstrates that optimized relay coordination not only improves protection performance but also plays a vital role in reducing arc flash hazards in industrial power systems.

Keywords: ETAP, IDMT, DMT, Incident Energy, FCT.

Downloads: | DOI: 10.17148/IJIREEICE.2026.14459