50-60 Hz electrical engineering represents a considerable potential ma
rket for superconductors. Fault current limitation will probably be th
e first among the possible applications, to find an industrial opening
. Exploited features are very specific of the superconductors, namely
the large contrast existing between an on-state with high current dens
ity and an off-state with high electrical resistivity, obtained as soo
n as the current reaches a specified level. It thus becomes possible t
o warrant the grid from any current excursion over a specified value,
with considerable impact on the protection and dimensions of conductor
s and devices, and increased possibilities of interconnexion. The curr
ent limiter technology is rather complex ; different structures have b
een proposed and tested ; they are resistive or inductive, based on lo
w-T(c) or high-T(c) superconductors. The most advanced candidate to da
te is a resistive structure, using conductors made of ultra-fine niobi
um-titanium filaments in a coppernickel matrix, whose essential featur
es are described hereunder.