A.C. Arc Flash Analysis: A new derivation method

This paper introduces a computation procedure for the ac Arc-flash, which is based on the radiated specific energy emitted by a hot body where the arch flash is present. To make the proposed method more accurate, the paper also introduces a function, based on the Paschen curve, which takes into account the non-linear behavior of the plasma generated by the arc-flash. The results obtained by the proposed method have been validated by comparing them with those derived by using the International Standard NFPA 70E, both in terms of boundary limit and specific radiated energy. The proposed method has a practical application in the evaluation of the electric hazard after the exposure to an arc-flash. Once this hazard is evaluated, the operator can determine the safety devices working on the under voltage electric plant. Moreover, all the results have been obtained according to Italian standard CEI 11-27 ed. 2014 and European standard CEI EN 50110-1.