Reduction of Short Circuit Current using DC Transmission and Split-Winding Power Transformer

This paper discusses a new scheme to reduce the level of fault currents in the feeder cable and power transformer windings under short-circuit conditions. The proposed scheme suggests splitting the feeder cable in two cables and connecting it to a network through two rectifier units. Therefore, the split windings of the power transformer are supplied by a six-conductor feeder using unidirectional dc current. Unidirectional magnetic flux produced by the windings are summarised in the transformer core resulting ac flux to ensure a normal transformer operation. The proposed scheme was analysed under short and open-circuit faults. It has been shown that the short-circuit currents in the cable conductors and transformer windings are reduced in 1.41 times in comparison to a conventional scheme.