Operational Characteristics of Hybrid-Type SFCL by the Number of Secondary Windings With YBCO Films

We investigated the operational characteristics of the hybrid-type superconducting fault current limiter (SFCL) according to the number of secondary windings. The SFCL consists of a transformer, which has a primary winding and several secondary windings with serially connected YBa₂Cu₃O₇ films. In order to increase the capacity of the SFCL, the serial connection between each current limiting unit is necessary. Resistive-type SFCL has a difficulty in quenching simultaneously between the units due to slight differences of their critical current densities. The hybrid-type SFCL could achieve the simultaneous quenching through the electrical isolation and the mutual flux linkage among the units. We confirmed that the capacity of the SFCL could be increased effectively through the simultaneous quenching among the units. In addition, the power burden of the system could be reduced by adjusting the number of secondary windings. We will investigate the method to increase the capacity through serial and parallel connections among current limiting units