A Study On Modeling And Optimization Method For Economic Operation Of Micro-Grids Under Uncertain Environment

Increasingly scarcity of Fossil fuel energy,environmental degradation,global warming,the development and utilization of renewable energy has become the focus of attention of governments.Increasing the proportion of clean distributed energy access to the grid,optimal control of each output of distributed power is the key to achieve its high efficiency and clean operation.However,stochastic volatility of renewable energy is strong,which makes it difficult to predict with high accuracy and brings huge challenges to the economic and efficiency operation of the microgrid system.For these problems,this thesis makes a research on the problems of optimal and economical operation of microgrids.Firstly,considering the uncertainty of wind power,photovoltaic and loads,establishing their statistical models,and on the basis of this proposing a consideration of uncertainty of microgrid economic operation online optimization modeling method.The modeling method is proposed to achieve the microgrid operation in the process of dynamic optimal control as the goal,through feedback and on-line optimization,reducing the impact of uncertainty on the microgrid and improving the economy and efficiency of microgrid operation.Secondly,considering the problem of online optimization model of microgrid has the characteristics of nonlinear,discontinuous and constrained conditions,and it is difficult to solve,this thesis focuses on the problem of online optimization of economic operation of microgrid,discusses the application of approximate dynamic programming method in solving this kind of problem,and designs a single approximate structure of approximate dynamic programming algorithm.Finally,a simulation model based on the European benchmark microgrid system is designed in this thesis,meanwhile,DigSILENT PowerFactory power system simulation software and MATLAB software are used in this thesis,which are through the method of software in the loop simulation to simulate and analyze the microgrid verification model.The simulation results show that the online optimization modeling method and the optimization algorithm proposed in this thesis improve the traditional methods5 shortcomings which is lack of information feedback,be unable to respond dynamically to the output power of the distributed generation unit and can not respond to the uncertainty of the microgrid online.Meanwhile,the method and algorithm overcome the influence of the random fluctuation of renewable energy and load and reduce the operating cost of the microgrid.