Switching and Decoupling Effects in a Single-Phase Transformer Using Extra DC Current

A single-phase current-limiting transformer has been developed based on flux transfer. The transformer consists of two independent iron cores, one primary coil, two separate secondary coils, and superconducting windings/loops. Two iron cores are in a mechanical contact and clamped. Superconducting windings/loops act as coupling/decoupling mechanism between two iron cores. The transformer has been made operational via a switchgear of the applied dc current for a potential use in the current limitation when the transition between the superconducting and normal (quench) states can be triggered. DC and ac currents can be applied simultaneously in fault and no-fault conditions to mimic the realistic cases of use. With decoupling ac energy transfer, we propose that conventional switching off may be replaced with the approach described.