Development of superconducting fault current limiting transformer (SFCLT) with the functions of fault current suppression and system stability improvement

We have been developing a superconducting fault current limiting transformer (SFCLT) with the functions of both transformers and fault current limiters. In this paper, firstly, we analyzed the operating characteristics of SFCLT introduced into a model power system with 3-phase, 500 kV/275 kV, 625 MVA and optimized the main parameters by EMTP simulation. Secondly, we designed and fabricated an experimental scale-down model of SFCLT with 3-phase, 275/105 V, 6.25 kVA, using NbTi superconducting wire, on the basis of simulations. Thirdly, we discussed the experimental results of the model SFCLT introduced into a transient network analyzer. It was finally revealed that simulation results and experimental results clarified the effectiveness of SFCLT having both functions of the fault current suppression and the system stability improvement in a future superconducting power system.