Echelon Energy Storage Participates In Wind Farm Power Fluctuation Stabilization Control Strategy And Optimization Configuration

In recent years,the number of electric vehicles has increased sharply.The power batteries in electric vehicles are affected by the vibration shock during the operation of the vehicle and the influence of daily charging and discharging,resulting in the growth of the internal SEI film and the generation of lithium dendrites,resulting in the decline of its capacity.The battery is generally used for 5-8 years and cannot meet the driving performance requirements and safety requirements of the vehicle.According to the test,when the power battery in the electric vehicle is retired,its actual capacity is about 70%-80%of the initial rated capacity.Most of the batteries still have good charge-discharge performance and capacity retention rate,and can be used in the field of mild-scenario energy storage after screening and reorganization.In the new power system,wind and other renewable energy will become the main force of power generation,but due to the influence of volatility,randomness and time-space mismatch,wind urgently needs to be matched with energy storage to reduce the impact on the power system.The application of retired batteries in the field of wind power storage can alleviate the retiring of a large number of power batteries.At present,the application strategy and economy of retired power battery are not clear,so the research and analysis of power battery cascade utilization strategy and economy has very important theoretical value and engineering value.At present,the retired power batteries are mainly Fe Li PO₄.This paper takes the retired lithium iron phosphate power battery as the research object,and analyzes the economics and application strategies of cascade energy storage in the scenario of smoothing wind power fluctuations.The main research contents are as follows:The economics of cascade energy storage is analyzed,and a life cycle levelized cost model considering capacity decay is established to evaluate the economics of cascade energy storage systems;the sensitivity analysis method is used to identify the key factors affecting the economics of cascade energy storage systems.And based on sensitive factors,the influence of different parameters of retired power batteries on the economy is analyzed,and the boundary value of cascade energy storage under different economic conditions is found.Considering the performance of retired batteries and the requirements of wind farms,a capacity allocation method for hybrid energy storage between retired batteries and new batteries in wind farms is proposed based on the optimal economy.The feasibility and necessity of hybrid configuration of retired battery energy storage and new battery energy storage are analyzed,and an action time scale model is established according to the characteristics of retired batteries to improve the charging and discharging behavior of retired batteries and better delay retired batteries life,improve the economy of cascade energy storage.A hybrid energy storage capacity allocation method with optimal economy is proposed,and the results of hybrid energy storage capacity allocation are obtained by using gurobi after linearization of the model.Based on the actual wind farm data,the hybrid energy storage capacity allocation and economy under different energy storage time requirements,different time scales and different control strategies are analyzed.In view of wind farm abandoning wind absorption and power fluctuation stabilization,a day-ahead and Intra-day two-stage operation strategy of wind farm based on shared energy storage absorption and cascade energy storage stabilization is proposed.Through the establishment of a day-ahead and Intra-day multi-objective two-stage optimization model,in which the upper layers of the bilevel model aim at minimizing the transaction costs between the power grid and all power generators,and the lower layer aims at minimizing the leasing of wind farms to shared energy storage and accepting the penalty cost of abandoning wind.Optimize the output of thermal power units and shared energy storage leasing.The intra-day model is based on the output of thermal power units and the transaction of shared energy storage capacity,and aims to minimize the assessment cost,abandoned wind power and electricity,reduce the fluctuation of wind power and reduce the impact of wind power grid connection on the stable operation of the power grid.Based on the improved IEEE-30 node system,the effectiveness of the proposed operation strategy is verified,and the operation of wind farm with shared energy storage stabilization,retired battery energy storage stabilization and retired battery energy storage grouping stabilization strategy is analyzed.