The effect of using minimum and maximum Utility fault contributions on Arc Flash study results - A case study

IEEE Guide for the Specification of Scope and Deliverable Requirements for an Arc-Flash Hazard Calculation Study in Accordance with IEEE Std 1584, recommends that alternate scenarios should be modeled considering minimum and maximum values of utility fault current, if actual utility fault current cannot be obtained from the utility company. This paper is a case history that proves the value of using minimum and maximum utility provided fault contribution at an industrial facility served by several 13.2 kV incoming feeders. Equipment in the facility includes a wide range of electric motors; VFD's and double ended motor control centers. Multiple scenarios were performed to account for the various complex modes of operation, and to present the worst-case arc-flash results.