What is ANSI C57.12.91?
IEEE Standard C57.12.91-2011 (Revision of IEEE standard C57.12.91-2001) is the IEEE Standard Test Code for Dry-Type Distribution and Power Transformers.
The purpose of this standard is to provide information regarding the procedures for the testing of dry-type transformers. Transformer requirements and specific test criteria are not a part of this standard but are contained in appropriate standards such as IEEE Std C57.12.01 or in user specifications.