IEEE C57.12.91-2020

This standard describes methods for performing tests specified in IEEE Std C.57.12.01 and other referenced standards applicable to dry-type distribution and power transformers, with a voltage of 601 V or higher in the highest voltage winding.2 It is intended for use as a basis for performance and for the proper testing of dry-type distribution and power transformers. This standard applies to all dry-type transformers including those with solid cast and/or resin encapsulated windings, except as follows: a) Instrument transformers b) Step-voltage and induction voltage regulators c) Arc furnace transformers d) Rectifier transformers e) Specialty and General Purpose transformers f) Mine transformers g) Testing transformers h) Welding transformers