Mixed three-phase and six-phase power system analysis using symmetrical components method

Abstract

The problem of analyzing a three-phase power system with six-phase lines interconnected by three-phase to six-phase transformers is studied. The approach used is based on the method of symmetrical components, which allows one to obtain a description of the whole mixed system either in terms of symmetrical components at three-phase sequences or in terms of symmetrical components at six-phase sequences. The research proves that this method can be implemented thoroughly and easily without the need to introduce too simplified hypotheses. The models of the six-phase lines and interconnecting transformers, at three-phase and six-phase sequences, are presented in order to obtain a completely homogeneous representation of the whole mixed system suitable for typical studies performed on power systems (load flow, fault analysis, stability studies).