Research Of A Medium And Long-term Load Forecasting Model And Method

The medium and long-term load forecasting of power system is to forecast the electric load for a period of 3 to 5 yeas even longer which meets the precision by considering the facts of operating characteristics, decision-making capacity, natural conditions and social impact. The medium and long-term load forecasting is supported to research the influence of economic and national policy for the reason that it is important for the long-term planning of grid reformation and expansion which is according to the economic development and load growth. It's necessary to improve the aurracy of the medium and long-term load forecasting with the establishment of power market which makes the planning conditions of power system more complicated and difficultBased on generalization of the course of development ,the accomplishment in the past decades and the development trends of prediction methods in this thesid,the advantages and disadvantages of Various mature methods and its application scope is compositely compared and synthesized. According to application of D-S evidence theory in various fields such as economic ,military and artificial intelligence, the possibility and applicability of it for the medium and long-term load forecasting is discussed in this article with the difficulty and improvement of the medium and long-term load forecasting is generalized. At first, the Gray Model (GM) and its improved model including k-weight Gray Model (kGM) and Equal Dimension Gray Model (EDGM) are applied for the medium and long-term load forecasting. And it tests and verifys the feasibility of the improvement for GM. Owning to the GM , kGM and EDGMwhich are used as basal models to forecast the medium and long-term load of a provincial grid,a new model based on D-S evidence theory (D-S model)is proposed. The resulsts show that it makes a great progress in prediction accuracy, which illustrates that it make a integration of the Advantages of three basal models. Furthermore, the improvement for D-S model is verifid with two new examples which are base on it.At the end of the paper, based on the disavantages of D-S model, the main problems of research and application of the medium and long-term load forecasting is analyzed and the futher work is prospected.