Development and characterization of Bi-2223 conductors for HTS transformer applications

Multifilamentary Bi-2223 tapes for AC applications in HTS transformers are studied. By twisting the filaments in tapes with AgMg sheath and Ag matrix the parallel field AC loss at power frequencies is lowered by more the 50% for the optimum twist length of 10 mm. The critical current density of these conductors corresponds to >80% of the non-twisted tape. In order to achieve a larger loss reduction tapes with Ag-alloys and ceramic barriers are studied.