Testing of machine wound second generation HTS tape Vacuum Pressure Impregnated coils

11th European Conference on Applied Superconductivity

Swaffield, D.^1 ; Lewis, C.^1 ; Eugene, J.^1 ; Ingles, M.^1 ; Peach, D.^1

General Electric, Power Conversion, Boughton Road, Rugby

CV21 1BU, United Kingdom^1

关键词: Differential thermal contraction;    High temperature superconducting tape;    Insulation resistance;    Insulation system;    Second generation (2G);    Second-generation HTS;    Superconducting rotating machines;    Vacuum pressure impregnation;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/507/3/032046/pdf
DOI  :  10.1088/1742-6596/507/3/032046

来源: IOP

【 摘 要 】

Delamination of second generation (2G) High Temperature Superconducting (HTS) tapes has previously been reported when using resin based insulation systems for wound coils. One proposed root cause is the differential thermal contraction between the coil former and the resin encapsulated coil turns resulting in the tape c-axis tensile stress being exceeded. Importantly, delamination results in unacceptable degradation of the superconductor critical current level. To mitigate the delamination risk and prove winding, jointing and Vacuum Pressure Impregnation (VPI) processes in the production of coils for superconducting rotating machines at GE Power Conversion two scaled trial coils have been wound and extensively tested. The coils are wound from 12mm wide 2G HTS tape supplied by AMSC onto stainless steel 'racetrack' coil formers. The coils are wound in two layers which include both in-line and layer-layer joints subject to in-process test. The resin insulation system chosen is VPI and oven cured. Tests included; insulation resistance, repeat quench and recovery of the superconductor, heat runs and measurement of n-value, before and after multiple thermal cycling between ambient and 35 Kelvin. No degradation of coil performance is evidenced.