Development of Critical Current Measurement System of HTS Tape Using Pulsed Current

The measurement of critical current for HTS tape at various temperature conditions if generally used by the conduction cooling system with dc power supply. However, the continuously increasing dc current affects the temperature rising of metallic parts such as copper terminal for conduction cooling, HTS tape holder, current leads, and contact parts by joule heating. The temperature increasing seriously affects the measuring factors, which are voltage, resistance, or temperature, and then users may get the wrong results. To minimize the heating effect, the authors considered the pulsed current instead of dc current for power supply. A cryostat for HTS tape has cryogenic refrigerant for conduction cooling and metallic current lead for 2500 A. The voltage and temperature variations by pulsed and DC current of the same HTS tape are given in this paper. The test results show the possibility of the measurement method for critical current using pulsed power supply with conduction cooling system.