A Superconducting Air-Core DC Reactor for Voltage Smoothing and Fault Current Limiting Applications

A superconducting air-core DC reactor (SACDCR) operated for both DC voltage smoothing under normal condition and fault current limitation under fault condition is presented. The novel SACDCR is formed by one superconducting air-core solenoidal inductor unit and one series-connected superconducting noninductive solenoidal resistor unit. The air gaps between the terminal layers of the superconducting air-core solenoid are optimized to achieve a higher critical current based on anisotropic traits and magnetic field distributions. The superconducting noninductive solenoid, which is inserted into the inner center of the superconducting air-core solenoid, experiences an increased background field under the fault condition and thus achieves better fault current limiting features compared with the same type of superconducting fault current limiter (SFCL) without a background field.