Development and Application of Fault-Withstand Standards for Power Transformers

After five years of effort, a working group of the IEEE Transformers Committee completed work on one of the most important new electrical standards to be developed in recent years, the Transformer Through Fault Current Duration Guide. This document defines the exposure limits of liquid-immersed transformers to short circuit currents, and establishes fault withstand guidelines for all conditions of service. This paper provides a description of these new standards and a brief history of how and why they were developed.