Study On The Day-ahead Purchase Model And Strategy In The Regional Power Market

In a single-buyer electricity market environment, the power grid company is subjected to the problem of purchase strategy from multi-providers of power. The purchaser needs to gain energy by relative lower price, but the generators would like to sell energy by higher electricity price. Obviously, their goals are to pursue maximization economic benefit for themselves in the power exchange market. In the electric power market, most of spot electricity transactions is realized in the day-ahead energy market. The day-ahead purchase strategy is the purchase planning that can achieve the maximum benefit for electric power system through considering constrains like load distribution spaces, security and transmission ability of power system, and purchase cost and transmission cost. The day-ahead purchase strategy not only influence security and economic of electric power system, but also power supply and energy sustainable development. That's why the research on the theory and approach of the day-ahead purchase strategy is of great focus and significance. However, because the strategy is related with two aspects: technology of power system and economy of electricity market, it has the characteristics of the complexity and the large-scale, the theory and approach of the day-ahead purchase strategy still have not been solved very well yet. In order to resolve the problem, the theory and approach of the day-ahead purchase strategy are studied systematically in this paper.Firstly, a new mathematic model of the day-ahead purchase strategy is presented. A object function is built by minimizing the total purchase cost , and the economic and security constrains from generators and power system are included in the model. At the same time, in order to solve the uncertainty of load forecasting of the optimal purchase model, the model is changeed into fuzzy chance constrained programming model.Secondly, a hybrid genetic/simulated-annealing algorithm is adopted for obtaining the reasonable solution.Thirdly, uncertainty decision theory is applied and five strategies are obtained under five rules, so that the optimization the day-ahead purchase strategy is decided according couple strategies.Finally, a algorithm program of Matlab6.5 language programming is achieved and through IEEE-30 node power system and North China 500KV power grid shows that the proposed model and algorithm is feasible and effective. At the same time, aday-ahead purchase strategy interface sysyem is built to use VC++ languageprogramming.