Analysis on fault current limiting and bus-voltage sag suppressing operations of SFCLs using magnetic coupling of two coils according to their application locations in a power distribution system

The application of the superconducting fault current limiters (SFCLs) using magnetic coupling of two coils in a power distribution system is expected to contribute to suppression of bus-voltage sag as well as limitation of a fault current. However, the performances of these types of SFCLs for the fault current limiting and the bus-voltage sag suppressing operations are affected by their design parameters such as connection form, winding direction, and inductance ratio of two coils. Besides, an effect of the SFCL on a power distribution system is dependent on their application location, i.e. at a feeder line and a secondary side of a main transformer. In this paper, for the analysis on the operations of these types of SFCLs according to their application location in a power distribution system, the power distribution circuit with the SFCL installed in the outgoing point of the feeder and the secondary side of the main transformer was constructed in a power systems computer aided design/electromagnetic transients direct current (PSCAD/EMTDC). With the PSCAD/EMTDC constructed for the power distribution circuit with this type of SFCL, designed with various design parameters' values for magnetically coupled two coils, the short-circuit simulations were carried out. Through the analysis on the results of the short-circuit simulations for the constructed power distribution circuit, the SFCLs applied into the outgoing point of the feeder, especially designed with the series connection and the additive polarity winding of two coils, were confirmed to be more effective for both the fault current limiting and the bus-voltage sag suppressing operations compared to the ones applied into the secondary side of the main transformer. (C) 2011 Elsevier B.V. All rights reserved.