Covered in this standard are all liquid-immersed distribution, power, and regulating transformers that are designed to operate at temperatures that exceed the normal thermal limits of IEEE C57.12.00 under continuous load, in the designed average ambient, and at rated conditions. Specific requirements and guidance in the design, testing, and application of the transformers covered within the scope of this standard are provided. High-temperature insulation systems or systems that use a combination of high-temperature and conventional insulation are incorporated by these transformers.

This standard applies to all liquid-immersed transformers that are designed to operate at a temperature rise that exceeds the limits of IEEE Std C57.12.00 under continuous load, in the designed average ambient, and at rated conditions.

This standard provides specific requirements for transformers which incorporate high-temperature insulation systems or systems that use a combination of high-temperature and conventional insulation.