Performance of a high-Tc superconducting fault current limiter-design of a 6.6 kV magnetic shielding type superconducting fault current limiter

Superconducting fault current limiters for electric power systems have been researched. A magnetic shielding type superconducting fault current limiter is developed in the authors´ research on superconducting fault current limiters. This limiter consists of a copper primary winding, a superconducting cylinder, an iron core and a control coil. The superconducting cylinder has a Bi2212 thick film on a MgO substrate. The control coil consists of some metallic rings, and the fault level can be adjusted by changing the number of the rings. To design a prototype limiter, the AC magnetic shielding and loss characteristics of small models were measured. The prototype limiter is 6600 V in rated voltage and 400 A in rated current. The superconducting cylinder is 0.45 m in diameter and about 1 m in height. Only the superconducting cylinder was designed to be cooled by liquid nitrogen. The experimentally manufactured limiter is about 1.3 m in width, about 0.6 m in depth and about 2 m in height.