IEEE C57.12.51-2019

This guide sets forth characteristics of ventilated dry-type transformers relating to performance, limited electrical and mechanical interchangeability, as well as recommended practice for installation of the equipment described, and to assist in the proper selection of such equipment. Specific rating combinations are described up to a base of 7500 kVA inclusive, high-voltage class from 1.2 kV to 36 kV inclusive, and low-voltage class up to 5 kV. This guide does not apply to other types of transformers such as specialty, sealed dry-type, pad-mounted drytype, instrument, step and induction voltage regulators, arc-furnace, mining, testing, welding, and rectifier transformers.