Three-phase backward/forward power flow solution considering three-phase distribution transformers

This paper proposes a three-phase backward/forward power flow solution which can handle distribution transformers of various common winding connections in unbalanced system of multi voltage levels. The proposed algorithm is based on the power summation method and takes the power losses into account considering the mutual coupling between three phases. The transformers are modeled by transformer nodal admittance matrix and mathematical formulas concerning to backward/forward sweep calculations of transformers are presented in detail for power summation-based process. The validity and effectiveness of the proposed method is demonstrated by the test results.