Abstract The winding technology with high current capacity is one of the important factors in power application of 20 MVA/66 kV-class superconducting power transformers. High-current power transformer is achieved by transposed conductors made of Rare Earth-based superconducting coated conductors. By transpositions, the improvement of uniformity of strand current distribution makes it possible to reduce the total number of strands and AC loss of coils. In this study, the high- T c superconducting coil was made by transposed 24 strands of 5 mm-wide Rare Earth-based superconducting coated conductors and operated at a current of 1 kA. The test results of AC and DC current characteristics and AC loss are reported.