Measurement Of AC Losses Of High Temperature Superconducting Tapes And Coils

Because AC losses of high temperature superconducting (HTS) tapes and coils have directaffects on the stability of HTS apparatus, the investigation of AC losses of HTS tapes andcoils has always been one of the most important research branches of HTS applications.Themeasurement of AC losses in HTS tapes and coils is important in qualifying the performanceof the superconductors and studying the mechanism of the AC losses.Therefore it is of greatimportance to establish an experimental bench to measure the AC losses of HTS tapes andcoils quickly and accurately, which may probably provide certain reference for the research ofHTS applications.In this paper, the conventional electrical method of AC losses measurement of HTS tapeswas systematically investigated and the existing problems were introduced. In order toovercome those problems and improve the conventional method, some suggestions weregiven and applied to measure the AC losses of a large number of HTS tapes. It was provedthat the experimental results agreed well with the theoretical results, which, in some sense,demonstrated that the improved electrical mothod was reasonable and workable.Based on alarge amount of experiments, an experimental bench to measure the AC losses of HTS tapeswas established, which has good maneuverability and repetition characteristic.Furthermore, we investigated the mothed of AC losses measurement of HTS coils.Uponthe anslysis of existing problems in the traditional electrical method, we come up with a newcapacitance compensated method for the measurement of the AC losses in HTS coils. Themethod was tested on one of the 3-phase coils of HTS Fault Current Limiter in our library.The experimental results were validated by comparison with theoretical datas.Finally, the problems on how to further improve the precision of the measurement systemwere discussed and some specific suggestions were proposed.