Characteristic Analysis And Experimental Research Of The Flux-coupling Type Superconducting Fault Current Limiter

With the continuous economic development of China,the demand for electricity continues to increase,and it is urgent to prevent the short-circuit current from exceeding the standard capacity.Applying a superconducting fault current limiter(SFCL)is an effective measure to limit the short-circuit current.The Flux-coupling type superconducting fault current limiter(FC-SFCL)adopts the tightly-coupled and low-loss parallel inductance coil,which can quickly respond and use the impedance to limit current.FC-SFCL can effectively reduce the capacity requirement for circuit breakers and ensure that short-circuit faults are reliably interrupted.In order to promote the practical application of the FC-SFCL,it is necessary to carry out characteristic analysis and experimental research on it.Based on the research status of SFCL,this paper has carried out the current-carrying experiments of superconducting tapes and coils,and conducted the characteristic analysis,designing,manufacturing and experiment of the FC-SFCL.The main work accomplished is as follows:(1)Considering the operating conditions and magnet type of the FC-SFCL,currentcarrying experiments of superconducting tapes and coils were conducted,the influence of external magnetic field and overcurrent on the critical current on the tape was studied,and the shunting of the parallel coils in the quench process was analyzed.The results can provide an important reference for the parameters design and control strategy of the FC-SFCL.(2)The current characteristics of the FC-SFCL under different control strategies were analyzed by simulation verified by experiment,and the voltage characteristics of the coil and breaker were obtained by experiment.Then the field-circuit coupled finite element model of the FC-SFCL was presented to study the influence of the winding ratio on the performance of the limiter,and the optimal winding ratio was selected to be 1.The theoretical calculation method for the voltage distribution of pancake-winding and layer-winding was proposed,and the simulation and experimental verification were carried out.The results showed that the voltage distributions obtained by the three methods are basically the same.(3)The basic structures and parameters of the FC-SFCL prototypes were selected,then pancake-winding and layer-winding prototypes with a core of the FC-SFCL were manufactured and tested,and the fault detection system and the 400 V experimental platform for the FC-SFCL prototypes was presented.The short-circuit experiments of the pancakewinding and layer-winding prototypes were carried out,then the difference analysis of the FC-SFCL prototypes was carried out.The results showed: the FC-SFCL could operate stably and the current-limiting ratio exceeded 40%,and large and medium sized SFCL prototypes should choose pancake-winding without core which is more advantageous.