This technical specification provides design@ testing and loading information for use by both the manufacturer and user of liquid-immersed power transformers using either high-temperature insulation or combinations of high-temperature and conventional insulation.It is applicable to?C power transformers designed in accordance with IEC 60076-1;?C convertor transformers designed to IEC 61378;?C arc furnace transformers@and covers the use of various liquid and solid insulation combinations.Whilst standards for traction transformers fall under the authority of IEC Technical Committee 9@ this specification however may be applicable as a guideline for the use of high-temperature insulation materials in traction transformers.