Optimal reactive-power dispatch using differential search algorithm

Optimal reactive-power dispatch (ORPD) is one of the most difficult optimization problems regarding to power-system operation which is heavily related to system stability. To overcome ORPD problem, in general, the total real-power loss is reduced by determining the power-system control parameters, such as generator voltages, tap ratios of tap-changer transformers, and compensated reactive power, optimally. In this paper, a simple and efficient heuristic search method based on the differential search algorithm (DSA) has been presented and used to solve the ORPD problem in power systems. The ORPD problem was overcome on the IEEE 30 bus and IEEE 57 bus test systems by achieving optimal solution sets of system control variables for the objective functions regarding to power-loss minimization, voltage-profile improvement, and voltage-stability enhancement. By comparing with the several optimization methods, the performance of DSA is tested and verified on the aforementioned power system. Optimization results of different cases and objective functions indicate the implementability of the proposed algorithm in terms of solving the ORPD problem as well as other single- and multi-objective optimization problems regarding to power systems.