IEEE C57.138-2016

This recommended practice covers routine impulse tests performed on distribution transformers, as required in IEEE Std C57.12.00(TM), and described in 10.4 of IEEE Std C57.12.90(TM)-20151. Distribution transformers covered by this recommended practice are liquid-immersed, single- and three-phase 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. This recommended practice covers only those aspects of impulse testing that are specific to routine testing of distribution transformers. For more thorough coverage of impulse testing of transformers in general, IEEE Std C57.98(TM) should be consulted.