VOLTAGE SPIKES IN SUPERCONDUCTING CABLE-IN-CONDUIT CONDUCTOR UNDER RAMPED MAGNETIC-FIELDS - PART-2 - ANALYSIS OF LOOP INDUCTANCES AND CURRENT VARIATIONS ASSOCIATED WITH THE SPIKES

A 27 strand hybrid superconducting Cable-in-Conduit Conductor (CICC) s ample (so-called TPX-PF model sample) has been fabricated and tested i n quickly ramped back ground magnetic fields. The voltage spikes that appeared in the sample's terminal voltages during magnetic field sweep s at DC transport current are analyzed using a model that calculates t he magnitude of individual strand current drops and the strand to stra nd/cable inductances associated with each voltage spike. Dependencies of the strand inductances and current variations with consecutive volt age spike numbers, total transport current in the cable and background magnetic field are analyzed and discussed. The analysis confirms prev iously reported suggestions that voltage spikes and the corresponding rapid variations, or jumps, observed in the conductor's local magnetic field are indications of rapid redistribution of current from one of the cable's strands in which the current reached its critical level. I t is shown that rapid current redistributions which are too small to i nitiate total cable quench lead to more uniform distribution of curren t among the strands in the CICC. Therefore, it may be possible to appl y small disturbances to a CICC to improve its strand to strand current distribution in a Gable and to stabilize its Ramp Rate Limitation beh avior. (C) 1998 Elsevier Science Ltd. All rights reserved.