Comparison of the Unbalanced Faults in Three-Phase Resistive and Matrix-Type SFCLs

The symmetrical components of the three-phase resistive-type and three-phase matrix-type superconducting fault current limiters (SFCL) were analyzed in the single line-to-ground fault and the double line-to-ground fault using symmetrical component calculus. Positive sequence current was highest in the resistive-type SFCL with a single line-to-ground fault and in the 380 turns matrix-type SFCL with a double line-to-ground fault, and negative sequence current was lowest in the resistive-type SFCL with a single line-to-ground fault. These indicate that and are determined from the total impedance of the SFCL and the uniform quenching characteristics of the superconducting element. Zero sequence current rapidly appeared from the three-phase resistive-type SFCL, but approached zero after three cycles. The application of magnetic field in the three-phase matrix-type induced the simultaneous quench of the superconducting elements, but a large amount of the symmetrical component appeared after three cycles from the fault occurrence due to the shunt resistor and the shunt reactor.