scope:

This recommended practice covers routine impulse tests performed on distribution transformers, as required in IEEE Std C57.12.00-1993, and described in subclause 10.4 of IEEE Std C57.12.90-1993.

Distribution transformers covered by this recommended practice are liquid-immersed, single- and threephase overhead-type up to 500 kVA; single-phase pad-mounted compartmental-type and underground-type up to 167 kVA; three-phase pad-mounted compartmental-type and underground-type up to 2500 kVA. These transformers are covered by IEEE Std C57.12.20-1988 through IEEE Std C57.12.26-1992.

This recommended practice covers only those aspects of impulse testing that are speciÞc to routine testing of distribution transformers. For more thorough coverage of impulse testing of transformers in general, the IEEE Guide for Transformer Impulse Tests, IEEE Std C57.98-1993, should be consulted.

Purpose

 This recommended practice is to assist manufacturers of distribution transformers in the setup and operation of a routine impulse test, and to assist distribution transformer users and purchasers in understanding the routine impulse test and how it differs from design tests.