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Arc-flash is a dangerous phenomenon that can occur during an arcing fault in an electrical system. People nearby may be subjected to extreme heat, light, pressure, and sound. Research regarding arc-flash has focused primarily on AC arc-flash due to the prevalence of AC electricity in the grid. However, the grid has begun to integrate more DC electrical sources as a result of decentralization efforts and environmental concerns. The increased proliferation of DC electrical sources demands research into DC arc-flash to assess the hazard as low-voltage DC sources have already become commonplace. Some DC arc-flash models have been produced to estimate incident energy. These models are either theoretical or semi-empirical in nature, as empirical research pertaining to DC arc-flash is scarce. The lack of empirical DC arc-flash data inspired a series of tests at American Electric Power’s (AEP’s) Dolan Technology Center (DTC) that were conducted in August 2018. These tests allowed the development of a limited empirical equation for incident energy. The research presented in this thesis is a continuation of the August 2018 DC arc-flash testing with the objective of generating an expanded incident energy equation. Furthermore, this research seeks to address the effects of some atmospheric conditions on the behavior of low-voltage DC arcs.

Arc flash is one of the two primary hazards encountered by workers near electrical equipment. Most applications where arc flash may be encountered are alternating current (AC) electrical systems. However, direct current (DC) electrical systems are becoming increasingly prevalent with industries implementing more renewable energy sources and energy storage devices. Little research has been performed with respect to arc flash hazards posed by DC electrical systems, particularly energy storage devices. Furthermore, current standards for performing arc flash calculations do not provide sufficient guidance when working in DC applications. IEEE 1584-2002 does not provide recommendations for DC electrical systems. NFPA 70E provides recommendations based on conservative theoretical models, which may result in excessive personal protective equipment (PPE). Arc flash calculations seek to quantify incident energy, which quantifies the amount of thermal energy that a worker may be exposed to at some working distance. This thesis assesses arc flash hazards within a substation backup battery system. In addition, empirical data collected via a series of tests utilizing retired station batteries is presented. Lastly, a predictive model for determining incident energy is proposed, based on collected data.

This thesis entitled, 'Development of the Impedance based Arc-Fault Determination Device (IADD)' details the development of a testing device that, when attached to an electrical node on the power system and through observations on voltage, current and phase shift with a step load change, determines the effective Thevenin or Norton impedance at the point of test. This thesis includes discussion of the theory and design process that enables the determination of an equivalent circuit, software development using National Instruments' LabView software development package and suggestions for future development. The purpose of this thesis is to produce a device that can accurately and correctly predict the expected bolted fault current at the test location of interest. The importance of accurately measuring phase shift to determine X/R ratio and bolted fault current by the IADD method is examined. Several other factors that effect system impedance, performance of the IADD, and the resultant NFPA arc flash hazard level are explored. The IADD has applications in both industrial/commercial applications and power distribution systems for determining system impedance. These applications are discussed. Several laboratory and field test cases are examined and conclusions are drawn on the performance of the IADD versus other methods of determining fault duty.