Research On Power Transmission Direction And Scale Of Interconnected Grid Considering Uncertainty

As the expanision of the scale of power grid,China has formed an interconnected national network.However,due to the uneven distribution characteristics of the energy resources and electricity demand,cross-regional power transmission is the inevitable choice for future power grid to realize the optimal allocation of national power resources.With the transition of China’s power grid to the third-generation grid,the large-scale development of renewable energy and the application of advanced technologies will both bring many uncertainties to the power system.Therefore,how to consider uncertainty factors in formulating the power transmission direction and scale scheme would be an important issue to be handled that.In this paper,the uncertainty of renewable energy output and grid technology development prediction are considered in studying the static power transmission problem,which respectively affects the accurate modeling of power supply and demand balance and the estimation of future grid development model.The uncertainty of renewable energy output runs through all possible future power grid development models,while the research on the uncertainty of grid technology development prediction is the premise to determine a certain development model of the future power grid and analyzing the power balance.To address the uncertainty of renewable energy output,an uncertainty processing method based on supply and demand analysis is proposed.By dividing the typical daily load timing curve into multiple load periods and analyzing the output characteristics of the wind and photovoltaic power in each period,the output scenario sets are generated and the corresponding power transmission planning model of sending and receiving end grid is established.Numerical example results show that,compared with the traditional method based on annual maximum load model,the method proposed satisfies the demand for electricity through a smaller cross-region power transmission scale and economic cost,improves the penetration rate of renewable energy,and reduces the impact of the uncertainty of renewable energy.To address the uncertainty of the development prediction of renewable energy generation technology and large-scale storage technology,a method based on typical scenario analysis for interconnected power grid power transmission planning is proposed.By classifying the possible development of technology,several typical scenarios of technology development can be obtained,and the evaluation index are used to compare and analyze the interconnection power transmission planning schemes of each scenario.Numerical example results show that the optimal allocation of cross-regional power resources is realized in all scenarios.Meanwhile,the high-level development of renewable energy generation technology can improve the clean energy penetration rate and reserve margin,and the high-level development of large-scale storage technology significantly reduce the scale of cross-regional power transmission and lead to the total cost of power supply down.Futhermore,in two technologies synchronous high level development scenarios the evaluation index are all improved.