Current Limiting Characteristics of a Flux-lock Type SFCL Using Two Triggered HTSC Elements

In this paper, a flux-lock type superconducting fault current limiter (SFCL) using two triggered high-Tc superconducting (HTSC) elements was proposed and its fault current limiting characteristics according to short-circuit location were analyzed. The flux-lock type SFCL with two triggered HTSC elements consists of two parts. One is two magnetically coupled coils with serial connection. The other, which is connected in series with the second coil, is composed of two HTSC elements in parallel connected through the normal resistor. Since the amplitude of the fault current depends on the fault location in case the fault occurs in a power system, the suggested flux-lock type SFCL can perform the fault current limiting operation through the quench occurrences of one HTSC element or two HTSC elements according to the amplitudes of the fault current. In case a low fault current, the fault current can be limited by utilizing only one HTSC triggered element. On the other hand, a larger fault current can be limited by two HTSC triggered elements. The short-circuit tests for the proposed flux-lock type SFCL according to the fault location were carried out in a feeder line of a power distribution system and its effective limiting operations could be discussed through the analysis on the short- circuit.