A 6.6kV single-phase fault current limiter (FCL) using high-Tc superconduct
ing coil as a limiting coil was developed, The development is a preliminary
step to investigate the feasibility of the FCL application for high-voltag
e transmission lines. The FCL is of the rectifier type and is mainly compri
sed of a limiting foil, a sub cooled nitrogen cryostat with a cryocooler? a
nd a rectifier bridge. The limiting coil, wound as a solenoid by Ag/Mn shea
thed Bi-2223 tapes, has an inductance of 30 mH. It is immersed in a liquid
nitrogen bath in the cryostat. A Gifford-McMahon cryocooler cools the cryog
en below 77.3 K. A pressure regulator keeps the cryogen at an atmospheric p
ressure. The coil has a critical current of 70 A at 64K; and endures a 50 H
z overvoltage of 22 kV against the ground. In a fault current limiting test
with a short-circuit generator, a short-circuit current of 12.5kA was limi
ted to 1.2kA.