scope:

This guide addresses the application of tertiary and stabilizing windings in liquid-immersed power transformers, as covered by IEEE Std C57.12.00, as well as recommendations to evaluate the need or convenience of having such windings. The primary application of this guide is for transformers and autotransformers with wye-wye-connected windings, with or without a delta-connected tertiary or stabilizing winding. The guide does not address tertiary windings in conventional delta-wye, or delta-delta-connected transformers.

Purpose

This guide provides users with a conceptual framework and recommendations for the specification, application, and performance evaluation of tertiary and stabilizing windings.