Research On Power System Source-grid-load-storage Coordinated Planning And Optimal Operation With High Proportion Of New Energy

With the goal of achieving carbon neutrality,carbon dioxide emissions peaking,and net zero emissions,the shape of China’s power system is constantly changing in the context of a high proportion integration of renewable energy sources,and renewable energy output is characterized by a high degree of uncertainty,the power system will also undergo major changes in methods and theories such as planning decision-making and dispatching operation.At present,represented by wind farms and photovoltaic power stations,renewable energy in China is mostly developed and integrated by centralized large-scale mode.In the regional power grid with large-scale renewable energy stations,similar wind sources or similar weather make the active power output of the same type renewable energy stations have strong correlation in the scales of space and time.As an important feature,the strong output correlation will inevitably have a huge impact on the planning and operation of the power grid in the planning year.At the same time,the access of a high proportion of renewable energy leads to a surge in the number of planning and operation scenarios,resulting in serious abandonment of renewable energy and insufficient system flexibility.To this end,it is necessary to carefully characterize and model the spatiotemporal correlation of the output of renewable energy stations,conduct in-depth research on the coordination of planning and operation,and propose a power grid planning method that suitable for the power system with high proportion integration of renewable energy.According to the existing correlation models and power grid planning methods,the spatiotemporal correlation of output between renewable energy stations are deeply analyzed in the paper,and based on this,a generation method of typical day set including extreme scenarios,a method of power system operation physical examination,and a source-grid-load-storage(SGLS)collaborative planning method with two-layer optimization model are proposed.Specifically,the following aspects are investigated.Aiming at the spatiotemporal correlation of new energy output,in this paper,the spatial correlation based on the variable structure copula theory is firstly described,a variable-structure points diagnosis method based on Z-test rolling verification is proposed,and the position of the sequence variable-structure points are obtained.For the sample sequence of each stage,the optimal variable structure copula model is constructed based on the multi-stage filtering method,such as to improves the fitting accuracy of spatial correlation.Moreover,the theory of stochastic differential equations(SDE)is employed to describe the time correlation,and an improved SDE model that strips seasonal components and considers long-term fluctuation trends is proposed to adapt to long-term time-series modeling with periodic and seasonal characteristics.Finally,the spatial and temporal correlation simulation sequences are generated respectively,and the sequences are reconstructed and sorted to obtain the spatiotemporal correlation simulation sequence of renewable energy.In order to obtain the sources-load typical scenarios of the power system in the planning year,this paper focuses on the analysis of the morphological characteristics of the sources-load curves on a daily time scale.The characteristic index system of the sources-load curves is constructed from the aspects of static measurement,dynamic measurement and complementary shape measurement,and the similarity,coupling and complementary characteristics of the sources-load curves are quantified.At the same time,taking into account the correlation features,geometric features,and probability features,the scenarios are reduced,and a more effective typical day set is obtained,it can depict and reserve extreme scenarios well.As a necessary condition for planning,this paper further proposes a power grid operation physical examination method in the planning year based on typical day set and optimal probabilistic power flow.Moreover,the grid congestion situation in the planning year is analyzed in detail.In order to cope with the challenges in terms of flexibility,coordination,security and stability brought by the high proportion integration of renewable energy into the power grid,this paper investigates the planning and operation coordination,the source-grid-load-storage coordination interaction mode based on the traditional power grid planning model.A two-layer SGLS collaborative planning model with planning and operation coordination under multi-operation scenarios is proposed.From the perspective of power grid construction,the upper-level investment and decision-making model aims to optimize the economy of construction and operation,while considering the renewable energy access rate constraint and the N-1 security constraint under preventive control.From the perspective of power grid dispatching,the lower-level multi-scenarios coordination and optimization operation model aims at the optimal weighted operation index composed of renewable energy abandonment rate and line flow unbalance degree,and considers source-grid-load-storage coordination interaction in the typical day set comprehensively.The proposed model can effectively ensure the robustness,economy,flexibility and coordination of the power grid.In order to further utilize the active interaction of sources and load,this paper proposes a SGLS collaborative planning model considering the constraints of the sources-load curves characteristics to improve the similarity and coupling degree of the sources-load curves.In addition,this paper studies and examines in depth the coordinated planning and optimal operation considering the spatiotemporal correlation of renewable energy output and the planned annual power grid operation physical examination.The research results in this paper can provide theoretical basis and application reference for the analysis of spatiotemporal correlation between time series,the generation of typical day set,the power grid operation physical examination in the planning year,and the SGLS coordinated planning under the background of high proportion integration of renewable energy.