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When planning for the installation of a 1.3-MW photovoltaic (PV) system and its integration into an existing facility's electrical system, an arc flash study was performed to determine the best protective device settings to minimize the arc flash energy in the PV system and to determine the effect of the additional short-circuit current on arc flash calculations for the existing system. The existing system has distribution at 13.8 kV and two 10-MVA transformers to a 2.4-kV feeder system. The PV system adds the hazard of 500-Vdc subarray collection wiring and terminations. The dc arc flash exposure of PV systems, including those in the inverter enclosures, can be complicated, and this paper outlines the basic data collected for the study, the steps taken to complete the calculations, the methodology used, the results, and the team's learnings. [ABSTRACT FROM AUTHOR]

In difficult economic times, companies sometimes delay the performance of maintenance on electrical power distribution equipment to save costs. If this happens, some circuit breakers (CBs) or protective relays will miss their scheduled maintenance and testing. This can create a significant safety risk if those protective devices are used to manage arc flash hazards. This paper describes a study method to determine which CBs and protective relays in a system are the most critical so that they can be prioritized for continued proper maintenance. [ABSTRACT FROM AUTHOR]

Electrical systems with AC voltage have been shown to exhibit arc flash incident energy during faults. Are there arc flash hazards related to dc systems, such as battery banks for UPS or drives, or dc buses used in chemical processes? Methods are available to estimate arc flash energy of ac exposures, but not dc. This paper will show the basic equations for maximum power from a dc arc and the resulting estimated arc flash incident energy. Research is required to find accurate values, but until research is completed, these equations can help the engineer provide a preliminary estimate of the thermal energy values for applying protective clothing for these exposures. [ABSTRACT FROM PUBLISHER]