AC loss properties in YBCO model coils for loss reduction

We have strategically promoted R and D activity for the development of elemental technologies in order to put into practical HTS power transformers applying YBa₂Cu₃O₇ (YBCO) coated conductors, focused on AC loss reduction in HTS coils. This paper shows AC loss reduction in model coils of YBCO tapes divided into five filaments by laser ablation. At first experiment, magnetization loss of YBCO tape with five filaments and YBCO tape with non-divided were firstly measured using a pick-up coil technology. Then, AC loss measurement is performed using two types of model coils of YBCO tapes with five filaments and non-divided, by two different technologies: an electric technique (i.e. 4-probe) and a calorimetric technique (i.e. boil-off). The results of the experiment show that the AC loss in the model coil of YBCO tapes with five filaments was reduced to one-fifth when compared with model coil of YBCO tapes with non-divided