The moving average method can avoid the large fluctuation of data. It is represented by the following formulas:

2.3 BP neural network

The BP neural network, which has a hidden layer, can improve the analysis ability of the network greatly, and it usually takes three layer network structures. The transfer function is significant to the neural network. It determines the ability and efficiency of the network to solve problems. Usually, Sigmoid function is selected as the transfer function:


Mid-long term load forecasting provides data support for power system planning departments when they need to make decision. The accuracy of midlong term load forecasting directly influences the rationality, economy of the power grid reformation and expansion, which has a profound significance to the development of power industry.