The effect of sectioning on superconducting fault current limiter operation

Various types of fault currents limiters have been proposed to reduce the fault currents in power transmission lines. The transformer type superconducting (SC) fault current limiter is one of them and has many advantages such as design flexibility. In normal operation mode the impedance is that of short-circuit transformer and has its minimum value. In the event of a load to fault an increase of the primary winding current causing a subsequent current increasing in the secondary SC winding (ring) and its quenching to the normal state. In this case the impedance turns to one in a no-load operation mode, i.e. is maximal performing the fault current limitation in the circuit to be protected. There has been investigated an effect of this sectioning of short-circuit SC windings or rings-on the operation. A configuration of the transformer with symmetrical alternatively positioned disc windings is shown to be the optimal.