Study on novel air-core transformer type SCFCL with a trigger winding

This paper proposes a novel air-core transformer type SCFCL with a trigger winding, with the combination of the superconducting tube, air-core transformer, a trigger winding, and triacs. The trigger winding placed outside the superconducting tube concentrically has negligible inductance because of the magnetic shielding of the superconducting tube, and rather low and unchanged voltage drop during the normal operation stage and appears a large induced voltage close to that on the secondary winding of the air-core transformer when the superconducting tube is quenched during the fault current-limiting stage. As a new type of FCLs, the novel SCFCL has advantages as followed: negligible impedance during the normal operation, instantaneous response to the short-circuit fault, fast recovery, low volume, low weight, and so on. Principles are investigated in detail, and verified by simulation results of the field-circuit coupled FEA method.