Winding techniques for conduction cooled LTS pulse coils for 100 kJ class UPS-SMES as a protection from momentary voltage drops

In order to develop the 100 kJ class UPS-SMES as a protection from momentary voltage drops, design of the conduction cooled LTS pulse coil was carried out and special winding machine has been developed. Such coil is required to simultaneously attain low AC loss and high stability and the distributions of temperature in the coil are sensitively controlled. For this purpose, an aluminum stabilized conductor with circular cross-section composed of a Cu stabilized NbTi Rutherford cable was used as the winding conductor, and in the winding process the twist angle of the conductor around its axis was controlled to adjust the direction of edge-on orientation to the Rutherford cable to direction of local transverse magnetic fields applied to the conductor in winding area of the coil. The developed winding machine is used for this winding method. As a result, conduction cooled LTS pulse coil can be expected to operate stably in adequate temperature margin.