Arc flash — New regulations and the advantages of the ultra fast grounding switch

摘要

According to NFPA 70E, arc flash incidents occur five to ten times each day. The occurrence of an arc flash is the most serious fault within a power system. The destructive impact of an arc flash event can lead to severe injuries to operating personnel, costly damage to the switchgear, and to long outages of the system. Active arc elimination systems can mitigate the above-named consequences. They extinguish an internal arc by redirecting the uncontrolled energy release into a defined and controlled bolted connection of all 3 phases to earth potential. Arc elimination devices are designed to detect and quench a burning internal arc in less than one third of a cycle and therefore offer the highest degree of protection for personnel and equipment. This paper encompasses the highlights of OSHA's Final Rule (forecasted to save 20 lives annually) that became a law in July, 2014 and a general overview of different arc flash protection devices available on the market. The Final Rule introduced new language, methods of calculations, and deadlines.