Preliminary Ageing Tests on a Superconducting Cable Dilectric

摘要

New dielectric tapes were developed for a superconducting, flexible, ac power cable. Preliminary aging tests were performed. Tests show that the proposed system withstood frequency accelerated aging at a cable stress of 10 MV/m for an equivalent 60 Hz time period of te 531 days under the cryogenic conditions of the proposed cable. The partial discharge inception stress for a helium density of 110 kg/m exp 3 declined from 12.3 MV/m at the beginning of aging to 7.1 MV/m at the end. This was thought to be due to the erosion of the vapor-deposited aluminum layer on the screen tapes. Although the dielectric tapes were exposed to partial discharge activity for almost the whole period of the test, there was no significant deterioration of the tapes. This suggests that damage due to discharges must be less at cryogenic temperatures. (ERA citation 05:020594)