A critical review of coupling loss results for cable-in-conduit conductors

AC loss curves measured for the same conductors at SULTAN (CRPP) and at University of Twente (UT) in higher and respectively lower frequency range are compared to draw consistent results. From the unified curves, the coupling time constant (n tau) to be used in the loss formulae is a function of frequency. The envelope of n tau vs. frequency provides a practical basis to predict the coupling current loss under specific operating conditions for those cable-in-conduit conductors where a single value of n tau is not adequate to describe the behavior over a broad range of frequency. The comparison of SULTAN and UT results is also extended to the case of cyclic load for NbTi CICC up to 10000 cycles. At UT, the load is applied on the cable by a mechanical press. At SULTAN, the same load is obtained by a combination of operating field and current (body force).