This standard specifies the terms and definitions, conditions of use, product classification and product model, basic parameters, technical requirements, test methods, inspection rules, nameplates, signs, lifting, packaging, transportation and storage of combined transformers. This standard is applicable to Oil-immersed combined transformers with a voltage level of 6 kV~35 kV, a rated capacity of 30 kVA~2 500 kVA, and a rated frequency of 50 Hz. For combined transformers with other frequencies or rated capacities, this standard can be used with reference to