Thermal and electrical stabilization of high-temperature superconductor powder-in-tube conductor

Abstract

High-temperature superconductor (HTS) powder-in-tube conductors often require thermal and/or electrical stabilization to ensure their long-term integrity. An example of such a stabilization need is the safety bypass lead of an HTS current lead intended for application to superconducting magnetic energy, storage (SMES) devices. The bypass lead functions include current sharing during upset conditions and conductor element temperature control. This paper presents a bypass lead design for an HTS current lead in an 0.5 MW h SMES system. Included are predictions of thermal and electrical stabilization and current lead heat leaks. The results of a supporting development program are presented, as are details of a method to connect conductor element/bypass leads, an assembly procedure, a cleaning method, and thermal-stress tolerance measurements.