scope:

This recommended practice document applies to liquid-immersed power transformers that are connected to generators subjected to significant short duration increases in the Volts per Hertz (V/Hz) ratio.

Purpose

The main purpose of this recommended practice is to provide procedures for developing design-specific V/Hz vs. time curves for use by manufacturers of power transformers. These curves provide recommended operating limits for different types of transformers, different designs and different insulation materials used in those power transformers. Such more accurate and more design-specific V/Hz curves aid users in the proper design and settings of protective relay protection systems for power transformers.