Preliminary Design of Pulse Inductor Applied for 100-kA Quench Protection System

The quench protection system in a large-scale superconductor test facility (LSTF) aims to protect the superconducting magnets from being damaged by long time and severe conducting current. A super-high pulse current from oscillation between a pulse inductor and a storage capacitor flows reversely into the main circuit to force the current in the main circuit cross zero, which ensures the reliable turn-off of the mechanical switch to protect the superconducting magnets. Furthermore, the pulse inductor also plays an essential role in adjusting the pulsewidth and the limiting pulse peak value. For the inductor, the pulse current is up to 130 kA and the rated inductance is 30 μH. To release the electromagnetic (EM) force largely and reinforce the structure and insulation properties, a circular multi-winding structure with epoxy resin-casting technique is presented. Based on the 2-D/3-D model built in finite element analysis software, the structure resist, deformation, heat, and EM environment of the design are simulated. The terminals are also optimized to minimize the damage from the EM force and extend the operation life of the inductor. In addition, a fatigue analysis is carried out to estimate the working life of the inductor and verify the reliability of the structure under the 130-kA pulse current working condition.