Research On Economic Operation Of Micro Grid Based On Power Market

In recent years, a profound reform of the structure of the electric power industry begins worldwidely. Countries are reforming in different patterns so as to achieve their respective goals.Our country formulates a reform plan named "four steps". The first policy implemented is:" plant-grid separation, price bidding ". At present, the " price bidding " has proceeded throughout the country in an all-round way. Because it can solve the problem of large-scale distrubuted power system combined to the grid and bring the energy efficiency of distributed generation into full play, micro-grid, as a new form of power system structure, is aroused extensive attention by experts at home and abroad. Because micro-grid includes PV power system and wind power generation which are influnced seriously by environment, it has dual identity:generator and consumer. As a generator, micro-grid has to consider its own economic benefits and costs of production in order to participate in power market and compete price bidding with other forms of power plants. To this end:it is of great importance to reseach on micro grid.The structure and connection mode of micro-grid system are illustrated firstly, its operation control methods and comprehensive control strategies are discussed on the aspects of micro grid and micro power. Various micro power node types are analyzed and transformed into ordinary PQ nodes, based on this, forward sweep flow algorithm which is adapted to micro grid is proposed. Reactive current compensation are introduced to improve the ability of the algorithm in processing PV nodes. Taking the test system with33nodes as an example, a detailed study of influence of connection grid location and capacity of micro-grid on voltage of micro grid and loss of system. Conclusion is draw from simulation:micro gas turbine has the most obvious improvement to the voltage and loss of power system; the support effect to the system voltage is most obvious when grid connects in the end of line, the overall loss of system is significantly reduced at the same time.Secondly, the power generation cost mathematical model is established according to the power generation characteristics of the various distributed power in power grid under the market model of " price bidding ", at the same time, power generation cost function model is established by considering the environmental pollution charges of photovoltaic power generation, wind power and other power generation unit. Power generation cost function model, environmental cost function model and comprehensive cost function model are built respectively under six different operation strategies of micro grid, the models fully embody the environmental benefits of micro grid.The algorithm of natural evolution particle swarm optimization (pso) based on the sinusoidal weight adjustment was came up with under the reseach of existing particle swarm. Study found that:the adopt of sinusoidal adjusting inertia weight can accelerates the convergence rate; the introduce of hybrid method not only can improve the particle diversity and avoid prematurity, but also can get the global optimal solution quickly.Combined with the load of a district, the last part of the paper analyzes the simulation of a specific micro power grid economic operation under six different operation strategies and three different optimization objectives, the output plans of the optimal operation among each micro power and plans of buying and selling electricity between micro grid and big grid are made. On one hand, the system obtain certain economic benefits by selling electricity during peak hours when the output of micro source is under its rated value,.on the other hand, it meets load demand by buying electricity during valley hours...