IEEE C57.109-2018

IEEE C57.109-2018 IEEE Guide for Liquid-Immersed Transformers Through-Fault-Current Duration

This guide applies to transformers referenced in IEEE Std C57.12.00 as Categories I, II, III, and IV.1 It sets forth recommendations essential for the application of overcurrent protective devices applied to limit the exposure time of transformers to short-circuit currents (see IEEE Std C37.91™ [B2]).2 This guide is not intended to imply overload capability.