Study on cause of quenching at the joint between multifilamentary superconducting cable and normal conducting cable using 3-D FEM

In order to investigate the cause of quenching at the joint between a multifilamentary superconducting cable and a normal conducting cable, the 3-D current distribution is analyzed. It is found that the cause of quenching is the extreme concentration of current in the joint due to the pronounced skin effect at liquid helium temperature. The mechanism of the concentration of current which is affected by the twist pitch and skin depth is also clarified quantitatively by numerical analysis.