The response characteristics of cowound voltage sensors in cable-in-conduit conductor

When a superconducting magnet is exposed to time-varying, non-symmetrical t ransverse and parallel fields, the balanced bridge for quench detection is ineffective. To make quench detection possible, the inductive voltage must be reduced, or canceled, to a level less than the resistive voltage due to quench. The internal cowound voltage sensors in the cable cross-section as the primary mechanism to cancel the inductive noise are analyzed and tested in this research. The signal to noise ratio under a variety of conditions with different sensor locations, field sweeping rates and quenched lengths are improved to a factor of 1000 or more by using cowound voltage sensors.