Research On Multi-objective Optimal Power Flow Considering Static Voltage Stability

Recently, the running of electric power systems is reaching their stability limit because of the constraint of economy and environment, and the influence of electric power market. In the electric power system, the probability of voltage becoming unstable continues to increase. In the traditional optimal power flow, the optimal objective is economic objective and voltage stability index is considered as the constraints, and this method can't ensure the optimality of system voltage stability. Consequently, it is important to ensure the optimality of system voltage stability in the calculation of optimal power flow. In this paper, static voltage stability index is added to the objective function of power flow optimization. The optimized objective function are the generation cost minimum, reactive power compensation capacity minimum, static voltage stability margin maximization.The model of multi-objective optimal power flow considering static voltage stability is proposed.According to different features of Jacobi matrix eigenvalue structure analysis and continuation power flow, a strategy is adopted, where Jacobi matrix eigenvalue structure analysis is used to achieve reactive power compensation position and continuation power flow is used to achieve static voltage stability margin.Because traditional optimized algorithms easily get into the local optimum point, Tabu search algorithm with strong"mountain climbing"ability is introduced to calculation of optimal power flow.The performances of the algorithm are evaluated by simulations on IEEE 14-bus system. Compared with primal-dual interior point algorithm, the simulation results show that Tabu search algorithm has better overall optimization performance and is a effective calculation method of optimal power flow.Considering that the system is running at the heavy load case, through Jacobi matrix eigenvalue structure analysis the reactive power compensation position is achieved in the calculation of multi-objective optimal power flow considering static voltage stability. The value of 0-1 decision variable in reactive power compensation capacity minimum objective function expressions is obtained. The fuzzy set theory and Tabu search algorithm are used to solve the problem of multi-objective optimal power flow. The method is evaluated by simulation on IEEE 14-bus system. The simulation results show that the model of multi-objective optimal power flow and the solution method can effectively realize the integrated optimization of the system voltage stability and economy.