Influence Analysis Of Superconducting Fault Current Limiters On Power System Transient Stability

The ever-increasing size of electric power systems results in increasement of the short-circuit current, this brings a serious risk to the safety of electrical equipment and the stable operation of the power systems. As a new type of fault-current limiting device, the superconducting fault current limiter (SFCL) has an obvious current-limiting effect and a good operational characteristic. Under a normal operating condition, the SFCL has a nearly zero-impedance characteristic, however, under a short-circuiting condition, its impedance abruptly increases to limit the short-circuit current. In this paper, the influence to transient stability of the SFCLs is investigated. First, the mathematic models of the different SFCLs are formulated. Then, according to the impedance characteristics of the SFCLs, their influence effects to the power system transient stability are studied based on the single machine to infinite system and two machine system models, and the time domain simulation is used to confirm the analysis results. Last, the influence effects of the SFCLs to the transient stability of multi-machine power systems are investigated by means of the time-domain simulation.