Current Limiting and Recovering Characteristics of Three-Phase Transformer-Type SFCL With Neutral Lines According to Reclosing Procedure

摘要

The requirements for the application of the superconducting fault current limiter (SFCL) to the power system include larger SFCL capacity, linkage with the protection system in the power system and reliable operation in the reclosing system. Among the requirements, securing the reliability of the reclosing operation is the most important factor to apply an SFCL to the power system. In the cases of line-to-ground faults, which frequently occur in the power system, the reclosing system removes the fault cause by separating the fault section. The power can be supplied again later by reclosing the breaker. The separating operation is conducted again if the fault cause has not been removed. After the separating operation of the breaker, the superconducting element that has limited the fault current must recover to the superconducting state within the breaker opening duration. In this study, the recovery characteristic of the transformer-type SFCL in the case of reclosing operation was analyzed. It was proved that the power burden must be uniformly distributed by the simultaneous quench of superconducting elements, for the superconducting elements to completely recover within the breaking time of the circuit breaker. It was also found that all superconducting elements recovered to the superconducting state within the breaker opening time. Thus, it was found that the transformer-type SFCL with neutral lines coordinates well with the reclosing procedure in the power system, due to the quick recovery of superconducting elements.