Novel inductive energization test method for high-temperature superconducting assembled conductors using an AC-excited primary coil

An inductive excitation method is being developed to conduct 6kA-class energizing tests of high-temperature superconducting (HTS) assembled conductors. To improve the measurement accuracy of the induced current using Rogowski coils, a new inductive excitation method was proposed, involving the application of an alternating current (AC) to the primary coil. The configuration of a 6kA-class AC inductive excitation method was investigated. To verify the principle of this configuration, an inductive excitation test was conducted using a one-turn short-circuit coil with a single HTS wire. At frequencies below 1 Hz, a phenomenon was observed in which the phase difference of the Rogowski coil voltage decreased rapidly when the peak value of the secondary current exceeded the critical current ( I C ) of the wire, suggesting the potential to determine the I C of the secondary coil. Using a lock-in amplifier for measuring the Rogowski coil voltage provided high resistance to noise and drift, enabling accurate measurements.