Comparison between self-field AC losses of a single-phase Bi-2223 cable measured by electric and calorimetric methods

High-T-c power cables based on Bi-2223 tapes are under development worldwid e. An important parameter for design and cost optimization is the AC loss e xpected during 50/60 Hz operation. Its measurement can be affected by sever al experimental problems that may alter the results. For this purpose, the 50 Hz losses of a 1.5 m long conductor, made by helically winding four laye rs of Bi-2223 tapes, were measured simultaneously by electrical and calorim etric methods in a wide range of currents up to 2 kA in order to investigat e the reasons for possible discrepancies. The present, specifically designe d, calorimetric system is not based on temperature distribution analysis bu t on the measurement of the gas boil-off rate of the liquid nitrogen bath. (C) 1998 Elsevier Science B.V. All rights reserved.