IEEE Standard

IEEE C57.12.00-1993 - Standard General Requirements for Liquid-Immersed Distribution, Power and Regulating Transformers.

IEEE C57.98-1993 - Guide for Transformer Impulse Tests.

IEEE C57.91-1995 - Guide for Loading Mineral-Oil-Immersed Transformers.                         

IEEE C57.12.36-2017 - Standard Requirements for Liquid-Immersed Distribution Substation Transformers.

NEMA ST-20: Dry-Type Transformers for General Applications.