This paper studies the problem of load forecast in electric companies. We combine the analysis of load cause and gray prediction model together, and enhance the accuracy of prediction, thus improving the economic benefit of electric companies and saving energy resources. Firstly, considering the cause of load, we separate load into three components: basic load component, weather-sensitive load component, and load component because of special events. Then, we take economic development and actual temperature into account to calculate load in each category. And then, we use gray prediction model to make a further prediction. The results show that gray prediction is only accurate in trend. In order to make a more accurate prediction, it should be combined with other forecasting methods. Finally, we combine cause of load with gray prediction model, and establish a combination forecasting model. The combination forecasting model explains the cause of load and the reason for error in gray model. With accurate forecast, it is easy for electric companies to manage their operation perfectly and get the most profit.
Application of Combination Forecast Model in the Medium and Long Term Power Load Forecast