Application Of Grey Theory In Mid-Long Term Load Forecasting

Load forecasting is an important research content of power system planning and running, belongs to stratagem forecasting, and is a premise for reliable supplying and economic running. In a planning period, the load and power demand decide the development scale and the development speed of power system, and also is the basis of power system planning and construction. Load forecasting makes the electric power or load of the whole planning region as forecasting object. It results decide the demand for electric power and the supplying capacity of distribution in thefuture. The results of load forecasting have important guidance significance for ascertaining the location of power supply and generating planning. Exact degree of load forecasting shall directly affect rationality of investment, network layout and running.Because the medium and long term load forecasting in network is affected by many uncertain factors, up to now, no methods can obtain the satisfying forecasting results at all instances. So at the time of practical forecasting, we should think about the practical situation and choose the appropriate model.At first, the thesis introduces the importance of load forecasting and its development actuality in domestic and international briefly, but also gives a summarization for load forecasting methods, then a thorough research into grey forecasting method is carried through. Through the research into modeling mechanism of grey forecasting method, the shortages of grey mechanism are found and some improved measures are put forward. Through thepretreatment and optimization to historical load data, the ability of grey forecasting dealing with fluctuant load data is strengthened, and the application range and forecasting precision are also enhanced; Through choosing a of developing coefficient, the precision of backdrop value is improved; By selecting initial condition, can make fit curve to match the rule of the things development in the future; By using equally dimensional new information grey model for forecasting, new information is used in the forecasting, which not only overcomes the shortcoming that the math model is changeless in simple grey forecasting method, but also makes use of the advantage of the high precision in short term grey forecasting. So it satisfies the request for the medium and long term load forecasting. By improving, the applicable range of the common grey model is enhanced. The improved model is compared with the common grey model by calculation example, which shows that the improved model has the advantages of small error and high precision. The calculation example of peak loadprediction and consumed power each year prediction of XIANG NING count proves that the improved grey model is a good forecasting method.