The prospects for HTS devices are predominantly seen in the energy sector and among the most promising future applications are superconducting fault current limiters (SFCL), electric power transmission cables, electric motors and magnetic levitation devices.

A superconducting fault current limiter (SFCL) is a unique device which is unparalleled in conventional technology.

Among all High Temperature Superconducting (HTS) power applications the SFCL today is considered the most promising device in terms of commercialization prospects.

The SFCL is an unique device, without any conventional equivalent, which limits the current as soon it oversteps a predetermined threshold value. It prevents the current from exceeding a given value. While it presents a negligible impedance in no fault regime (no voltage drop), it naturally and automatically inserts a high impedance above a given current and the SFCL impedance automatically disappear after the fault clearance and a certain delay.

The resistive SFCL brings an innovative device in the electric grid, which need it to respond to new demands in terms of power quality and security of supply. A FCL also enhances the operation of an electric grid and will play a part in the grids of the future (smart grids). Today the fault currents are only cut when they cross zero (several zero crossings are necessary to definitively extinguish the electric arc) but they are not really limited in amplitude. All the fault currents must not overstep the limited cutting capacities of the switchgears. Impedances are put in the grid to limit the fault current amplitudes but they introduce among other things permanent voltage drops and losses under no fault operations.

This today operation prevents from high voltage quality and supply of some loads or grid parts. The simplest way to secure a supply is indeed to multiply the supply paths, but it increases the short circuit current (sum the short-circuit currents of the different paths), which is often not possible since it oversteps the short circuit clearing capability of the switchgear.