DEVELOPMENT AND TESTS OF A FLEXIBLE SUPERCONDUCTING BUS-LINE FOR THE LARGE HELICAL DEVICE

A flexible superconducting bus-line is proposed as an electrical feede r between the superconducting coils of the Large Helical Device (LHD) and the device's power supplies. The bus-line consists of superconduct ing cables and a cryogenic flexible transfer-line. A specially develop ed aluminum stabilized NbTi/Cu compacted strand cable satisfies requir ements for large current capacity, high stability, high reliability an d flexibility. A full-scale model with a length of 20 m was designed a nd constructed to investigate the feasibility and performance of the s uperconducting bus-line. Its fabrication, transportation, installation , cooling and excitation tests were successfully carried out. The bus- line was very stable and could be excited up to 40 kA (rated current i s 30 kA) without a quench. The stability, current distribution, heat l oad were also measured.