Estimation of the Engineering Critical Current Criteria for HTS Wire Carrying an Alternating Current

This paper deals with a method to estimate the engineering critical current criteria for high temperature superconducting (HTS) wire in alternating current (ac) operation. There are plenty of high temperature superconducting devices used in ac operation, such as superconducting fault current limiters and superconducting cables. However, the operating currents of those ac superconducting devices are mostly designated by the critical current measured in direct current operation based on International Electrotechnical Commision (IEC) 61788-3, so the engineering critical current criteria of the HTS wire for ac operation is needed. In this paper, the engineering critical current criteria of HTS wires for ac operation are estimated considering the odd harmonic electric fields, the calculated ac loss, and the temperature. The authors expect that the method and approaches used in this study will help to estimate the engineering critical current and to decide the operating currents of HTS applications.