Consensus Phase Shifting Transformer Model

The model of regulating transformers used in classic power system studies, such as load flow analysis or state estimation, is still debatable. A recent publication has demonstrated that the two alternative tap-changing transformer models usually found in the literature and power system simulation software packages may lead to important discrepancies, especially at extreme tap positions. This work is an extension of the aforementioned publication, written by the same authors, with the aim of reconciling those models for the case of the phase shifting transformer (PST). This work demonstrates that prevailing formulations of PST, particularly of the asymmetrical type, may also lead to important discrepancies when operating far from the nominal tap, with a different impact depending on the power factor of the power flowing through the device. Furthermore, a general model for the PST is proposed in this contribution. The new model uses the same data available in traditional formulations leading to improved results and avoiding any ambiguity.