Characteristics on the Transformer-Type SFCL According to Reclosing Operation the Voltage Increase

Fault current in power system is expected to increase by demand of power capacity. Therefore, when the fault occurred, fault current was increased in the power system. Many studies have been progressed to limit the fault current. Superconducting fault current limiter (SFCL) is one of them which has been studied in worldwide. In this paper, we will analyze characteristics of a transformer-type SFCL by reclosing operation when the voltage increases. Twice opening times in the reclosing of circuit breaker were set as the 0.5 and 15 seconds, respectively. Turn's number of primary and secondary coils set 4:2 and we increased voltages from 120V to 280V for each experiment. By the current waveform, maximum fault current in second and third cycles was lowered when the voltage was increased. In the recovery waveform, recovery time was increased as the voltage was increased. The reason was that power burden of the SFCL increased when consumption power was increased, so the time to get back to SFCL took longer. We compared the characteristics of a resistive-type and transformer-type SFCL. As a result, we found that the fault current of a transformer-type was lower than resistive-type and recovery time of the SFCL was shorter. Consequently, transformer-type SFCL was more profitable for limitation of fault current and recovery time under the same condition for reclosing operation.

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