Design and Basic Test of SFCL of Transformer Type by Use of Ag Sheathed BSCCO Wire

Superconducting fault current limiters (SFCLs) are promising devices to reduce the fault current constraint when designing and operating power systems. SFCLs must meet requirements for precise operation, operating impedance, recovery time, and so on. SFCLs using YBCO thin film or bulk BSCCO meet some of these requirements. However, it is quite difficult to satisfy the requirements for precise operation and recovery time. A transformer type SFCL with an adjustable trigger current level can enhance the precision of operation and fulfill the requirements for SFCLs. It needs long wire; however, long high temperature superconducting (HTS) wire like Ag sheathed BSCCO, is not considered suitable for SFCL because its resistance in its normal state is very low. This paper describes the design of an SFCL of transformer type by use of wire of very low normal resistance and basic testing of a trial SFCL using this design.