Experimental Study Of Improved Bridge Type Superconducting Fault Current Limiter

The principle of "Bridge type superconducting fault current limiter(SFCL)" isimproved. A resistance is connected to the rectifier bridge to limit the state value offault current.Three kinds of improved bridge type SFCL are proposed: resistance-switchbridge type SFCL, hybrid bridge type SFCL and active bridge type SFCL. The faultlimiting process of three structures is studied and simulated, together with the keyelement parameters.Involved in the construction of " 600V/60A three phase bridge type SFCL testbed". A short-circuit fault stimulator is designed, which could stimulate familiarshort-circuit fault in power system. Further more, it can control the duration andinterval of fault accurately.Using the testbed, experimental study of two structures are carried out. It isshowed that the improved bridge type SFCL has a very good performance to limitboth the peak value and state value of the fault current. The resistance-switch bridgetype SFCL act quickly and effectively in both cases of single fault and double fault.Further more, it could recover quickly and make the system re-close action possible.The hybrid bridge type SFCL could act by itself in fault, but has a too long recoverytime to adapt to the system re-close action. Therefore, a parallel switcher or anotherlimiting system is necessary in this type.In addition, the over-current characteristics of Bi-2223/Ag tape is studied and anon-inductance coil is made, as an useful attempt to make resistance type SFCLusing superconducting tapes.