New Forecasting Method Of Source Load Power In Rural Power Network And Application In Distribution Network Planning

The energy structure of China is gradually reforming,and the energy supply is changing from fossil energy to renewable energy.The source load structure of distribution network has also undergone tremendous changes.The source of the distribution network includes not only the large power grid,but also renewable energy power generation,such as wind energy and solar energy.To the load side of the distribution network,in addition to the conventional loads,electric vehicle charging load and the "coal to electricity" load are also appeared.However,the new source and loads often have a certain randomness,which has a certain impact on the distribution network planning.Source load prediction is an important basis for distribution network planning,but the traditional load forecasting methods can no longer meet the requirements of new distribution network planning.Considering the different characteristics of the distributed photovoltaic power generation,electric vehicle load and "coal to electricity" load,the power prediction methods of the three aspects are studied.Considering the randomness of light intensity and weather type,a distributed photovoltaic output prediction method based on two-layer probability model is discussed.Considering the strong uncertainty of the time and space distribution of electric vehicle load,we discuss an electric vehicle charging load forecasting method based on the combination of owner trip chain and Monte Carlo stochastic simulation method.Based on the correlation between residents’ conventional electricity load and "coal to electricity" load,we discuss a load forecasting method of "coal to electricity" based on Copula theory.In order to solve the problem of distribution network planning,the technical principles of distribution network planning are first given,It includes grid planning,line equipment selection and technical requirements for access of distributed power supply and electric vehicles.Secondly,based on the analysis of the classical model,a planning optimization method aiming at the economic operation of the distribution network is proposed.The objective function of minimum investment cost and optimal system operation index is established,and the corresponding solution method is given.Take Dali County,Weinan City,Shaanxi Province as the application object of the proposed method.Firstly,the development status of Dali County power grid is described.The forecasting results of distributed photovoltaic,electric vehicle load and "coal to electricity" load in Dali County are obtained by using the proposed power forecasting method.Then,the existing problems of Dali County power grid in the planning level year are summarized,and planning county power grid with the proposed method.The results show that the five indexes concerned of 10 kV lines are all improved significantly,including the operation load rate,voltage loss,total capacity of distribution transformer,power supply radius and connection degree.