Interior point cutting plane method for discrete optimal power flow with ideal transformer model

In this paper, the traditional II equivalent circuit used to model the transformer is replaced by an ideal model in discrete optimal power flow (DOPF) formulation, which introduces a fictitious bus to express the power and voltage converting relations of the tap-changing transformer, so the admittance matrix is fixed during iterations to reduce computational efforts. Furthermore, this representation of transformer helps DOPF problem to be decoupled into two subproblems, which can improve computational efficiency greatly. Interior point method is used to solve continuous active power subproblem, and interior point cutting plane method (IPCPM) is adopted to solve discrete reactive power subproblem. Unfortunately, we find that the convex combination solution appears with great probability when solving DOPF problem, so in this paper IPCPM is improved to repair this shortcoming. Numerical simulations on IEEE 14-300 test systems show that the improvement of IPCPM is efficient, and the proposed method is suitable for solving DOPF problems for large-scale systems.