The analysis of the fault currents according to core saturation and fault angles in an inductive high-Tc superconducting fault current limiter

In this paper, we investigate the fault currents in an inductive high-Tc superconducting fault current limiter (SFCL). The currents can cause serious damage to the reliability and stability of the power system. To analyze the transient fault characteristics of the SFCL, we fabricated an inductive high-Tc SFCL and tested it under different fault conditions. To simulate a fault condition, a fault angle controller was connected to a load. As the firing angle of the triac in the fault angle controller was controlled, various angles of the fault instant can be selected. An important parameter for the design and the fabrication of the SFCL is the reduction of the fault currents. If abnormally high currents due to low impedance of SFCL do not occur in the network with SFCL, the currents flowing under fault conditions can be limited to a desired value within one cycle. The fault current reduction depends on saturation, normal zone propagation velocity, turns ratio, and the fault angle (the instant of the fault occurrence within a cycle).