HIGH-TEMPERATURE SUPERCONDUCTING CURRENT LEADS FOR MICRO-SMES APPLICATION

SMES is being applied on a microscale (1-10 MJ stored energy) to impro ve electrical power quality. A major portion of the SMES refrigeration load is for cooling the conventional (copper, vapor-cooled) current l eads that transfer energy between the magnet and the power-conditionin g equipment. The lead refrigeration load can be reduced significantly by the use of high-temperature superconductors (HTSs). An HTS current lead suitable for micro-SMES application has been designed. The lower stage of the lead employs HTSs. A transition between the lower stage a nd the conventional upper-stage lead is heat-intercepted by a cryocool er. Details of the design are presented. Construction and operating ex periences are discussed.