IEEE
IEEE C57.12.91 is a published standard from the IEEE that serves as the test code for dry-type distribution and power transformers. It describes how the verification tests on these transformers are arranged and carried out, so that results from different laboratories, factories and field crews can be compared on a common basis.
Editions cited: IEEE C57.12.91
The document is a test code: it concerns how tests on dry-type transformers are performed and reported, and not what the finished product must be. It covers the arrangement of the unit during a test, the connections and measurements involved, and the way the outcomes are presented, across the family of routine, design and other verification tests that dry-type units undergo, including the dielectric tests that prove insulation strength. Transformer manufacturers use it to run and certify factory testing, purchasers use it to specify what must be demonstrated before shipment, and testing engineers use it as the reference for repeating dielectric and related tests during commissioning or after repair. It works alongside the general-requirements document for the same transformer family. This page describes the document in original words and does not reproduce it. For the procedures, limits and tables, obtain a licensed copy of IEEE C57.12.91 from the publisher.