A Unified Power Flow Model for Three-phase Transformers in Medium and Low Voltage Distribution Networks

The transformer model is a particularly important part of the power system. Currently, some researchers are committed to building a more accurate transformer model. Based on the existing transformer $\pi$ type equivalent circuit, this paper proposes a concise unified power flow model for three-phase transformers in the medium and low voltage distribution network. The model built in this paper considers the influence of the zero-sequence current path on leakage admittance and excitation admittance. Simultaneously, the symmetrical component method is used to express the influence of interphase coupling, and the phase shift matrix is introduced to realize the different phase shift relations. Based on the IEEE 4 bus system, the effectiveness of the unified power flow model is verified.