비대칭 고장전류 저감을 위한 초전도 한류기 투입저항 결정 방법

When fault currents contain decaying DC offset, first cycle peak value is higher than steady-state fault current value. The magnitude of DC component depends on fault initiated angle and X/R ratio of power systems. These characteristics can affect the performance of protective devices. Therefore, asymmetrical current reduction is important for power system. For reduction of asymmetrical current, the auxiliary Superconducting Fault Current Limiter (SFCL) connected in series main SFCL is designed with first half cycle operating characteristics ahead of the quenching of main SFCL. In this paper, we propose decision scheme of insertion resistance in auxiliary SFCL for reduction of asymmetrical fault current using the half-cycle equation. EMTP/ATPDraw simulations are conducted to verify the effectiveness of proposed scheme.