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Description
The manufacturing of superconducting magnets for High Energy Physics (HEP) and Fusion Energy Sciences (FES) applications requires high-current conductors to generate stronger magnetic fields without increasing the inductance of the magnet. Increased inductance is undesirable due to the associated AC losses, which reduce the temperature margin; and the quench protection also becomes complicated. Testing high-current superconductors with a direct current room temperature power supply is unfeasible for two primary reasons: 1) the limited capacity to supply large currents, and 2) the significant heat load losses at the current leads. A superconducting current transformer offers a solution to both of these challenges. A 50kA superconducting current transformer is planned for manufacturing and commissioning at Brookhaven National Laboratory as part of its user facility upgrade. This current transformer will facilitate the testing of superconducting cables, conductors, joints, and insert coils under high magnetic field conditions (10 T) and with currents up to 50 kA. To evaluate the manufacturing process and validate the theoretical models, the magnet division has developed and tested a 15kA prototype transformer. This prototype can deliver 15 kA to the test sample for up to 13 minutes, assuming a secondary resistance of 10nΩ and an inductance of 1μH. A closed loop digital control system has been implemented to ensure precise current delivery to the sample. This paper presents the experimental results from these tests.
Keywords: superconducting transformer, fusion, accelerator, test facility, high field testing.
