Optimal power flow comprising congestions and voltage management by global quadratic optimization of active and reactive power

By changing active and reactive power to counteract the increasing number of multiple congestions and multiple inadmissible voltage deviations in the grid of ENTSO-E, grid losses are influenced significantly as well. Thus, different available measures against the aforementioned off-limit conditions can differ not only in their efficiency due to off-limit conditions but also in regard to grid losses. Furthermore, measures for power flow optimization can cause or worsen off-limit conditions. Since grid losses cannot be optimized with linear approaches a quadratic approach is needed for the objective function. Its derivation considering a distributed slack according to control reserve and its application is shown in this paper. The linear constraints of the optimization (e.g. thermal current limits and voltage bandwidth) are derived as well. The novel approach by combining optimal power flow and optimized congestion management delivers a global optimum even with nonconvex functions, fast and reproducible results and a proper prediction.