Quench Protection Optimization of Multi-Coil LTS Magnets

Quench protection is critical for superconducting systems, especially those containing significant energy to damage the system or its components during quench. We propose a new quench protection approach for multi-coil low temperature superconducting (LTS) magnet systems. The approach minimizes the number of protection components that must be activated during quench. In this approach, inductively-coupled coils are electrically connected in several possible ways: all in parallel; several parallel-connected groups, with each group consisting of several series connected coils; several series-connected groups, with each group consisting of several coils in parallel. If one of the parallel-connected coils or groups quenches, current in this coil or group decreases while current in the other parallel-connected coils or groups tries to increase to keep the total magnetic flux in the circuit the same, and this tendency will be affected by the nature of the inductive coupling among the coils. If during this event the non-quenching parallel coils remain superconducting, then the quench is limited to only the quenched coil or group. In some cases, the equipment may continue operation after quench, although at a somewhat reduced capacity. The proposed approach is potentially more advantageous for superconducting systems that consist of many weakly-coupled coils of similar size.