High temperature that the invention is not be the impedance of the coil generating a magnetic offset between the two coils wired to the same core is caused, the impedance by being not support the self-destructive composed of resistance occurs in the high temperature superconducting device in the event of an accident to limit the fault current it relates to a superconducting current limiting. The invented device is magnetically coupled to a voltage is induced in the additional power, without at the same time, the tertiary winding and the incident if installed so applied the magnetic field coil applies a magnetic field to the tertiary winding to the high temperature superconducting device, the magnetic field to the high temperature superconducting device at the same time as the accident is applied by being there are also features an increase in the phase transition resistance possible. Also characterized in that by controlling the duty ratio of the power switch to the tertiary winding with the magnetic field applying coil which can control the size of the fault current is limited and the size of the magnetic field applied to the high temperature superconducting device.; According to the present invention controls the duty ratio of the power semiconductor device without having to adjust the tap of the tertiary winding to control the magnetic field magnitude to be applied in accordance with the threshold characteristic of the high-temperature superconducting bulk or thin film element formed by applying to adjust the size of the magnetic field number and, where the advantage of reducing the size and volume of the applied magnetic field through a high frequency switching operation coil and is possible by giving adjust the duty ratio, accident normal conducting resistance scale, which results can control the fault current magnitude. In addition, since the bulk or thin film of high-temperature superconducting current-limiting element ratio it is lower than the resistance-type high-temperature superconducting current limiters to operate in exclusive hereafter there is an advantage capable of increasing the breaking capacity.
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