Experimental 7.2 kV(rms)/1 kA(rms)/3 kA(peak ) current limiter system

A current limiter system based on GEC ALSTHOM's kA-class AC superconducting conductors was realized. Its active components are two parallel noninductive superconducting windings, a shunt resistor, and a detection box which triggers the opening of a fast circuit breaker. The current limiter system has to withstand in the superconducting state current up to 1 kA(rms), and to provide without damage an immediate limitation at 3 kA(peak), in the various fault conditions which could to appear on one of the three phases of a 7.2-kV (rms) network. The conductor definition guarantees complete transitions, and therefore maximal protection, whether in the case of a short circuit or of an accidental quench. Applications to the AC power network are examined for protection against excessive short-circuit currents. The current limiting system reduces considerably the fault current, its destructive effects, and the switching capacity of the required circuit-breaker. The current limiter system has been tested in a 600-MVA power station