This work presents a new approach for the resolution of Optimal Reactive Power Flow problem. In this approach, the inequality constraints are treated by the Modified Barrier and Primal-Dual Logarithmic Barrier (PDLB) methods. The inequality constraints are transformed into equalities by introducing positive slack variables and are perturbed by the barrier parameter. A Lagrangian function is associated to the modified problem. The first-order necessary conditions are applied to the Lagrangian function generating a nonlinear system, which is solved by Newton's method. The perturbation of the slack variables results in an expansion of the feasible set of the original problem, allowing the limits of the inequality constraints to be reached. Numeric tests using the CESP and the SOUTH-SOUTHEAST BRAZILIAN systems and a comparative test with PDLB method indicate that the new approach is efficient in the resolution of Optimal Reactive Power Flow problem.
Power System; nonlinear programming; Primal-Dual method; Newton's method; Modified Barrier function