Energy Storage Configuration For DC Power Grid With Large Scale Wind Power Integration

With the gradual depletion of traditional fossil energy resources and the increasingly prominent environmental problems,it has become an international consensus to develop new energy and reduce carbon dioxide emissions.Wind power technology has been developing rapidly for its advantages of mature technology,low power generation cost and wide distribution of resources,and has been developed and utilized on a large scale.The inverse distribution between wind power resources and load centers and the uncertainty of wind power generation hinder the large-scale wind power consumption in China.The combination of flexible DC transmission technology and energy storage technology provides a feasible way to realize the large-scale wind power consumption in China.In this context,this paper conducts a study on the energy storage configuration of the DC transmission grid with large-scale wind power integration,in order to improve the wind power consumption capacity and operation economic efficiency of the system through the configuration of battery energy storage.The main research results are as follows(1)An optimal configuration model of energy storage for DC transmission grid is proposed,and the model is convexized through piecewise linearization,cone relaxation and large M method.Based on the historical data,the single day with the largest peak valley difference of system net load in each season is selected as the typical day of the season.The multi terminal DC power grid with wind power convergence is simulated,and the configuration results under different energy storage costs and wind abandonment penalty coefficient are compared.The results show that the wind power consumption capacity and operation economic efficiency of the system is improved by configuring battery energy storage,which verifies the effectiveness of the proposed model and method.(2)In order to make the planning results reflect the time series operation characteristics of power system,a DC grid energy storage configuration model based on time series production simulation is proposed.The model is in the form of bi-level programming.The outer model uses particle swarm optimization algorithm to optimize the energy storage configuration scheme.The inner model is used to plan the annual operation scheme and calculate the annual operation cost of the system.Through the simulation based on the annual historical data of load and wind power output,the energy storage configuration scheme and system operation results which can effectively consider the time sequence operation characteristics of the power system are obtained.On this basis,the initial and final state of charge of the energy storage is included in the optimization scope,and the planning results further improve the wind power consumption capacity and operation economic efficiency of the system.(3)In order to make the planning results fully consider the uncertainty of wind power output,a data-driven DC grid energy storage robust optimization configuration model is proposed,which uses historical wind power output data to establish a generalized convex hull form uncertainty set to represent wind power output uncertainty.The wind power output limit scenario is extracted from the uncertain set,and the model is solved through the C&CG algorithm.The energy storage configuration scheme and system cost under different wind power limitation are compared.The results show that the scale of energy storage configuration can be reduced and the system operation economic efficiency can be improved by allowing a certain scale of abandoned wind.(4)In order to select the optimal energy storage configuration scheme,an evaluation method based on analytic hierarchy process(AHP)is proposed.The comprehensive effect of energy storage configuration scheme is measured by the utilization rate of wind power,system regulation capacity,economy and environmental friendliness,and different energy storage configuration schemes in this paper are evaluated.The evaluation results show that the scheme based on the time series production simulation of DC power grid energy storage configuration model has the best comprehensive effect in the scenario constructed in this paper.