1.1 This standard prescribes insulation levels and dielectric test requirements for power transformers where : (1) The transformer insulation levels and dielectric test requirements are explicitly specified to be in accordance with this standard (2) The transformers are to be operated at system voltages from 115 kV through 230 kV (3) The transformer has a rating, either singlephase or three-phase, equal to or greater than 30 000 kVA self-cooled or 50 000 kVA forcedcooled 1.2 These requirements, when specified, supersede all requirements relative to insulation levels and dielectric tests as contained in ANSI/ IEEE C57.12.00-1980 [4] ' and ANSI/IEEE C57.12.90-1980 [ 51. 1.3 Unless explicitly specified, this standard shall be considered as excluded in the event of any blanket reference to all current standards.