Design of the 3 phase 60 MVA HTS transformer with YBCO coated conductor windings

In this paper, a 3 phase 60 MVA high temperature superconducting (HTS) transformer was designed with YBCO coated conductor windings and its characteristics were analyzed. First, an automatic calculation program for HTS transformer design was developed, in which the Ic-B characteristics of HTS tape was considered. Using the calculation program, basic dimensions of windings and iron core were determined and electromagnetic field analysis was performed for the loss computation. Finally, efficiency, weight and wire length of HTS transformer with coated conductor winding were calculated. The efficiency was over 99.9%, which is higher than that of any conventional transformer. The weight of the HTS transformer was about 16.6 tons and the length of HTS wire was about 47 km when the voltage per turn is 89.7234. Moreover, the magnetization AC loss of coated conductor winding was very small compared with that of BSCCO-2223 winding. To reduce the AC losses, we introduced the low current density winding method in all windings and the magnetization loss was reduced to about 66% of that of general winding.