Using a MILP-based model for solving the optimal power flow problem in distribution networks integrated with step-voltage regulators
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https://doi.org/10.54939/1859-1043.j.mst.112.2026.64-72Keywords:
Optimal Power Flow (OPF); Mixed-integer linear programming; Step-voltage regulators (SVR); Distribution network; Local Marginal Price (LMP).Abstract
This paper proposes a mixed-integer linear programming (MILP) model for the optimal power flow (OPF) problem in distribution grids with step-voltage regulators (SVRs). The OPF problem aims to minimize the total cost of the distribution grid, including the cost of purchasing effective and reactive power from the transmission grid, the cost of generating effective power, and the reactive power of distributed power sources. The constraints considered include the power flow equations, the node voltage constraints, the branch transmission power limits, the power factor limits at the connection point, and the SVR constraint. The MILP model of the OPF problem in the distribution grid was developed from the mixed-integer nonlinear programming (MINLP) model by linearizing the power flow equations and building an accurate linear SVR model. The proposed MILP model is evaluated on an IEEE33-node grid with different load scenarios using the GAMS programming language and the CPLEX commercial solver. The calculation results show that the MILP model is computationally efficient, and the optimal pressure distribution of SVR reduces the operating costs of the distribution grid.
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