Additional AC Loss Properties of Three-Strand Transposed Parallel Conductors Composed of REBa2Cu3Oy Tapes

The additional AC loss due to forming three-strand transposed parallel conductors with REBa
₂
Cu
₃
O
_y
(REBCO, RE = rare earth) superconducting tapes, are investigated theoretically and experimentally. In this study, supposing that the two transposition points deviate by arbitrary length from optimal ones in three-strand parallel conductor, the theoretical expression of the additional AC loss was derived. For the derivation of theoretical expressions, the voltage-current characteristics of REBCO tapes were taken into account by using a
n
-value model. The additional AC loss was measured via pick-up-coil method under an applied AC magnetic field with various amplitudes and frequencies. The validity of the theoretical expressions was confirmed by accordance between theory and experiment.