We are developing high-temperature-superconductor (HTS) current loads for a 1-MW/1-kWh modular SMES system. In the modular SMES system, a pair of current leads would be installed in each module so that the heat load to the low-temperature end through the leads is minimized. Design study of the lead configuration including the safety lead and its thermal characteristics is presented herein. The safety lead composed of stainless steel is placed in parallel to the bulk HTS.
A test unit for verification of safe operation has been developed and the simulated bulk HTS quench test has been demonstrated. The maximum temperature of the safety lead reached 200 K and the terminal voltage of the safety lead was only 1.2 V in the case of a 1000-A quench test. This temperature rise was well below the designed value. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 120(1): 23–32, 1997