A method for cooling a transformer and transformer apparatuses are implemented. A transformer apparatus, according to one embodiment, comprises: a conduction cooled electrical transformer (240) mounted to a cold plate (252); and a heat pipe (262) for supplementing cooling of the transformer (240), the heat pipe (262) comprising a first end (303), a second end (305), and a sealed low pressure cavity containing an amount of a fluid (311), wherein the first end (303) of the heat pipe (262) is located in a hot region of the transformer (240), the second end (305) is maintained colder than the first end (303) by contact with the cold plate (252), and heat produced at the first end (303) by operation of the transformer (240) is moved to the second end (305) by a closed loop vapor cycle in the sealed low pressure cavity using the fluid (311) of the heat pipe (262).