Fundamental characteristic estimation based on finite element method for magnetic shielding type superconducting fault current limiter

The superconducting fault current limiter is expected to be the first application of high-Tc superconductors (HTSs) in power systems. To develop a magnetic shielding-type superconductor fault current limiter, we have carried out some fundamental experiments on the magnetic shielding characteristics of an HTS bulk cylinder. In this paper, the experimental results of magnetic flux penetration into Bi-2223 cylinders are shown. An ac magnetic field is applied to the sample by a primary winding (copper coil) excited by ac triangular- and sinusoidal-waveform currents in the frequency range from 0.1 Hz to 100 Hz. We also developed a finite element method computer program for evaluation of the dynamic electromagnetic behavior of the HTS cylinder in a time-varying external magnetic field. The results of computer simulations considering the voltage-current (E-J) characteristic are compared with experiments. Next we carried out a current-limiting test with a small limiter model, and the developed finite element method computer program successfully simulated the electromagnetic behavior in current-limiting operation.