Research On Economic Dispatch Of Wind-storage Combined System Based On Lithium Battery Discharge Depth Power Processing

As the proportion of new energy sources such as wind power continue to increase and eventually become the main electrical energy contributor to my country’s power system,it will also stimulate the continuous growth of the scale of energy storage deployment.When energy storage occupies a certain position in the system and long-term response to wind power output fluctuations,the life loss caused by changes in its operation mode will increase the cost of wind farms is a problem that cannot be ignored.Therefore,this article is dedicated to constructing an economic optimization model for the combined wind-storage system,and coordinating the effect of the wind farm response plan and the use of energy storage,taking into account the life loss of energy storage,to maximize the benefits of the wind farm.Firstly,this paper studies the optimal modeling theory and method of wind-storage combined system considering the uncertainty of wind power output.The characteristics and topological structure of the combined wind-storage system are analyzed.By analyzing the characteristics of wind power output,a basic model considering the forecast error of wind power output is established.Through the division of energy storage types and the analysis of the operation characteristics of lithium batteries in electrochemical energy storage,the basic model of lithium batteries is constructed.Secondly,this article chooses a lithium battery life attenuation model suitable for optimized configuration scenarios.Based on the analysis of the lithium battery life attenuation mechanism and the factors affecting the life loss of lithium batteries,the characteristics and applicability of the current lithium battery life attenuation model are summarized,and the most suitable model is selected according to the requirements of the wind-storage joint system optimization scenario in this article.Lay the foundation for constructing the wind-storage joint system revenue model.Then,in order to solve the problem that the variables of the basic model of lithium battery life loss cost do not meet the model solution requirements in the power system scheduling optimization scenario,this paper performs power processing on the depth of discharge of lithium batteries,and transforms the basic model of lithium battery life loss cost.On this basis,a wind-storage combined system economic dispatch model based on deep discharge power processing is constructed.The model comprehensively considers wind farm electricity sales revenue,wind-storage combined system output deviation penalty,lithium battery operation and maintenance costs,and lithium battery life loss cost,and set its power ramping constraints especially for the life management of lithium batteries.Finally,this paper conducts a simulation analysis on the economic dispatch model of the wind-storage combined system based on the deep discharge power processing.The simulation is carried out from two aspects: the technicality of wind-storage combined system scheduling and the economics of wind-storage combined system scheduling.The convergence of the particle swarm optimization algorithm used in the model is also analyzed.The simulation results show that in the process of jointly coping with wind power fluctuations by the combined wind-storage system,considering the life loss of lithium batteries and paying attention to the management of their charge and discharge constraints can bring considerable benefits to the wind farm.