Influence of DC Offset Transport Current on AC Loss Characteristics in HTS Tapes

In this paper we present the experimental results of the loss of the high temperature superconducting (HTS) tape in AC and DC mixed electro-magnetic condition. The DC magnetic field is not of concern, because its influence parallels the critical current variation. The electro-magnetic environment consists of the DC offset transport current, the AC transport current and the AC magnetic field. The experimental results described were measured by the electric and calorimetric methods in the same section, and we establish the feasibility of measuring the loss using the electric method in AC and DC mixed electro-magnetic conditions. The experimental results show the loss components of the joule loss, AC transport current loss and magnetization loss. DC offset current affects the total loss characteristic in a DC and AC mixed electro-magnetic condition. Especially, when the peak transport current exceeds the critical current, the losses are increased, because there is a period when the current density is greater than the critical current density.