Modeling of Transport Loss in Bi-2212 Round Wires: Effects of Local Defects and Non-Uniformity

In this paper, based on the three-dimensional (3-D) H -formulation, we calculate the influence of local defects and non-uniformities on the AC loss in HTS round wires. By comparing intact round wires and round wires with local defects or non-uniformities, we found that when the peak value of the transport current is less than the critical current at the “bottleneck” of the defect, the difference between the two is small. When the peak value of the transport current is greater than the critical current at the “bottleneck” of the defect, the AC loss will increase significantly. The increase in the non-uniformities of the round wire makes the AC loss gradually increase. The increase in the pitch of the inhomogeneous distribution of the round wires will gradually reduce the AC loss.