The bridge-type fault current controller - a new FACTS controller

The operation of a novel current controller, which can also function as a fault current limiter and as a solid-state AC circuit breaker, is presented. The controller, which consists of a thyristor bridge, an inductor and an optional bias power supply, is installed in series with the voltage source and the load. For load current values smaller than a preset value, the inductor of the current controller presents no impedance to the AC current flow. For values higher than the preset current value, the inductor is switched automatically into the AC circuit and limits the amount of current flow. Theoretical results in the form of circuit simulations and experimental results with a single-phase unit, operating on a 13.7 kV three-phase system with peak short-circuit currents of 3140 Arms, are presented.