Study Of Multi-Objective OPF Based On Power System Economy And Stability

Recently, the running of power systems is reaching their stability limit because of the constraint of economy and environment, and the influence of electric power market. In the power system, the probability that voltage is becoming unstable continues to increase. In the traditional optimal power flow, the optimal objective is single economic objective and voltage stability index is only considered as the constraints, and we cannot guarantee that it will have the better coordinated relations between the systemic economy and stability. Consequently, premising economy of power system, it has the vital practical significance how to enhance the stability of system. In this paper, static voltage stability index is added to the objective function of the optimal power flow. According to different features of every quiescent voltage stability analysis method, a strategy is adopted, where Jacobi matrix minimum mold eigenvalue of convergent flow is used to express the static stability margin of current system operating point, the model of multi-objective optimal power flow considering the static voltage stability and the system economy is proposed. Also, considering the generation cost and active loss as economy of power system, the optimal objective functions are the generation cost minimum, reactive loss of power system minimum, static voltage stability margin maximization.Becauset the traditional optimal algorithms easily get into the local optimum point, the accumulation sufficiency evaluation strategy and the overlapping operator concept with maintaining the population the multiplicity as well as reflecting population individual density information better is introduced to calculate the optimal power flow, and the NSGA-II algorithm has been inproved through it. Next, the NSGA-II algorithm exist the defect such as restraining unsteadiness, jogging speed, prematurity, and so on. So the TPDE algorithm is introduced to take place of the overlapping and the variation operation of the NSGA-II algorithm, so that the better restraining effect and the globally optimal solution can be obtained.In order to confirm the validity of the improved algorithm, the performances of different algorithm are evaluated by simulations on IEEE30 bus system. Compared with NSGA-II algorithm, the simulation results show the improved algorithm has better overall optimal performance and is an effective calculation method of optimal power flow. At the same time it can implement the efficient synthesis of the voltage stability and economy of power system effectively.