Quench and Recovery Characteristics of Series-Connected Resistive Type SFCLs With Magnetically Coupled Shunt-Reactors

We investigated quench and recovery characteristics of series-connected resistive type superconducting fault current limiters (SFCLs) with magnetically coupled shunt-reactors. The slight difference in critical currents between high-Tc superconducting (HTSC) elements, especially connected in series, causes uneven quenches, which makes it difficult to increase the voltage capacity of SFCL. To solve this problem, several methods such as the application of magnetic field and the shunt-resistor across individual HTSC element have been suggested. The suggested method in this paper is to use the magnetically coupled shunt-reactors instead of the shunt-resistors. The experimental equipment of the series-connected resistive type SFCLs with magnetically coupled shunt-reactors was constructed and the current limiting experiments were performed. Through analysis for the current limiting experiments using both the magnetically coupled shunt-reactors and the magnetically uncoupled shunt-reactors, the magnetic coupling between the shunt-reactors was confirmed to be more effective for the balanced power burden of the series-connected HTSC elements comprising the resistive type SFCL with its faster recovery time.