Effect of fault resistance on the behavior of superconducting fault current limiter in power systems

Current limiting behavior of a superconducting fault current limiter (SFCL) depends on the prospective fault current, which in turn depends on fault resistance. Accordingly, this paper introduces a comprehensive study on the effect of fault resistance on the behavior of SFCL in power systems. A model for the system under study and SFCL is developed using PSCAD/EMTDC software. The fault resistance is changed from a very small value (0.5 Ω) to a large value (25 Ω). At each fault resistance, the line currents are obtained with and without using SFCL. It is shown that SFCL effectively reduces prospective fault currents, even at small fault resistances and high fault currents. Furthermore, the percentage limitation is determined as a function of fault resistance. It is demonstrated that SFCL behaves as an adaptive scheme, where its percentage limitation becomes higher at high fault currents. Finally, the current limiting burden of SFCL is evaluated at different fault resistances through the voltage across the SFCL.