Effects of Longitudinal Field in a Multiply-Twisted Superconducting Cable

초전도다중케이블에서의 축방향자계

Multiply-twist cable is used for a large capacity superconducting cable because it is helpful to reduce AC losses and to increase transport current. In a multiply-twisted cable, the axis of a strand does not coincide with that of cable. Therefore, the longitudinal field is generated by the transport current. The longitudinal field changes the current distribution in the strand and generates additional AC loss. This paper calculates the longitudinal field that is applied to a strand in the multiply-twisted cable. Current distribution of a strand in the cable is also presented. 2nd level superconducting cable is chosen as an analysis model, whose current capacity is 2000A. Calculation result shows the longitudinal field cannot be neglected in low field machines such as superconducting transformer.