Study On Dynamic Economic Dispatch Of Wind Integrated Power Systems

With the increase of energy demand and depletion of global fossil oil resources, wind power generation has been paid more attention as a good alternative to thermal energy power generation. However, different from conventional generators, the large-scale integration of wind power generators has associated operational challenges due to its uncertainty and variability. As a result, it becomes more and more necessary to study the dynamic economic dispatch (DED) issues in wind power integrated system. The corresponding model and method have been investigated in this paper.Firstly, the general overviews of optimization techniques used in the paper are presented. The optimization principles of particle swarm optimization (PSO) algorithm and nonlinear primal-dual interior point (IP) method are analyzed in detail. The PSO global searching ability is improved by applying maximum deviation function, feasible regulation scheme and mutation regulation scheme. This paper proposes a new hybrid methodology combining these two methods. The proposed method is developed in such a way that the improved PSO algorithm is applied as a based level search, which can give a good direction to the optimal global region, and a local search primal-dual IP method is used as a fine tuning to determine the optimal solution at the final. Investigation indicates this method is suitable for solving the optimaztion model with nonlinear, noncovex and multi-peak-value characteristics and a higher quality solution can be obtained.Then the influence factors of DED issue in wind integrated power systems are analyzed. In the optimization model, the constraints of up spinning reserve and down spinning reserve are introduced to deal with the influence of wind power forecast errors on dynamic economic dispatch. The valve point effect is also considered in the objective function. That is to say, the optimization model is of non-differentiable characteristics. On the basis of smoothing technology, this paper applies the hybrid PSO and IP algorithm to calucate the global optimal solution.Based on the above DED model, the probabilistic distributions of wind speed and load forecast errors are introduced to describe the uncertainty in power systems. So a modified DED optimization model with wind power penetration is proposed. In this model, the risk based up and down spinning reserve constraints are considered. The required up and down spinning reserve costs are also included in the objective function, which stand for the costs caused by the risk of shedding load and penalty of wasting energy respectively. Using the proposed model, a reasonable scheduled output of wind power can be obtained. Simulation results of a system with ten conventional generators and one wind farm demonstrate the effectiveness of the proposed method.Finally, the DED issue for Liaoning power system integrating large wind farms is analyzed and discussed to validate the practicability of the proposed methods. It can be concluded from simulation results that the dispatch scheme determined by the risk reserve constrained DED model with wind power penetration shows its superiority in regard to comprehensively and reasonably reflecting the requirement of risk and cost in power systems.