Decision of optimal insertion resistance of superconducting fault current limiter for reducing asymmetrical fault current

This paper proposes an application of superconducting fault current limiter (SFCL) to reduce the AFC, especially decision method of optimal insertion resistance of SFCL. The proposed method employs an auxiliary SFCL and main SFCL connected in series. The optimal reducing level of AFC is that the peak value of AFC is limited to steady-state fault current. Based on this concept, the equation to determine the resistance of SFCL is developed. The distribution system and SFCL is modeled by an electromagnetic transient program (EMTP)/ATPDraw to verify the effectiveness of the proposed method. The simulations according to the existence of SFCL and X/R ratio of source impedance are performed and the results are analysed.