Study of the medium-long load forecasting based on the identical dimension addition grey model

The principle of identical dimension additional prediction was discussed based on the Grey theory in this paper. The identical dimension additional dynamic grey model in the medium-long term load forecasting had been put forward in the power system, and the annual load value in this region of 1999-2009 was forecasted by modeling on the basis of this region´s historical load data. According to inspection of the posterior error and relative error caused by the forecasting results, the following could be realized. This method has the advantages of the need of less samples, the higher forecast precision, the faster calculating rate, and it is a practical medium-long term load forecasting method in the power system.