The simulating research on a improved magnetic shielding type of HTSCFCL

The magnetic shielding type high temperature superconducting fault current limiter, which mainly consists of a primary copper coil, a high-Tc superconducting cylinder as the secondary winding, an iron core and a sub-cooled nitrogen cryostat with a cryocooler, can reduce both the transient and the steady-state fault current significantly, but, the device will reduce the limiting impedance in the HTSCFCL if the magnetizing flux reached the saturation point in the magnetic path having no air gap. A improved magnetic shielding type high temperature superconducting fault current limiter is developed and analysized in the paper. The limiter mainly consists of a copper coil, a superconducting cylinder, a control copper ring, an air gap and the three-legged magnetic core. The copper coil on a superconducting cylinder for generating an AC magnetic field, the superconducting cylinder for shielding the field, the control copper ring for controlling fault currents and the air gap in the three-legged magnetic core for avoiding magnetic saturation under the higher current. The simulation results show the limiter can make the time for recovery shorter, and effectively avoid the reduction of a limiting impedance in the HTSCFCL if the magnetizing flux reached the saturation point.