The improved magnetic shield type high T/sub c/ superconducting fault current limiter and the transient characteristic simulation

Based on the equivalent circuit of a power transformer, considering both the nonlinear magnetizing characteristic of an iron-core and the nonlinear resistance of a superconducting secondary winding (V-I characteristic), the simulation of a magnetic shield type high T/sub c/ superconducting FCL was carried out by Simulink module of Matlab software. The transient response, especially the primary short circuit current is obtained. The influence of the saturation of an iron-core, and the specified structure of the magnetic circuit are analyzed. Based on the simulation, an improved magnetic shield type HTS FCL, a cross section adjustable power transformer with a multi-turn superconducting secondary winding is proposed. Its advantages include stable apparent impedance during the occurrence of a fault, shorter recovery time and lower voluminal energy dissipation during controlled S-N transition.