| In order to achieve the carbon peak and neutrality goals,the construction of a new power system dominated by renewable energy is accelerating in China.With the grid integration of large-scale renewable energy represented by wind power and photovoltaic power,the inherent random volatility and intermittency of renewable energy seriously threaten the safe,stable,and economic operation of power system.Energy storage is a dispatchable resource with the property of flexible charging and discharging,which can effectively compensate for the volatility of renewable energy generation,and improve the flexibility of power system.Due to the high investment cost and long payback period of energy storage system,if its capacity is configured only to meet technical goals,it will greatly reduce the economy of the construction.In addition,the multiple performance requirements of power system lead to a diversified demand for energy storage,which is difficult to be met by a single type energy storage technology.A hybrid energy storage system composed of two or more types of energy storage can greatly improve its applicability to power system.Therefore,this paper takes hybrid energy storage system as the research object,discusses how to achieve large-scale renewable energy grid integration through collaborative configuration of different types of energy storage in the new power system.The specific contents are as follows:Firstly,a hybrid energy storage system selection model based on AHP-MARCOS method is constructed.Based on the analysis of energy storage characteristics,a index system for type selection that reflects energy storage characteristics in terms of technology,economy,and environmental dimensions was constructed.Taking two problems that need to be solved by energy storage as demand scenarios(suppressing fluctuations of renewable energy output,peak shaving and valley filling),AHP method is used to assign weights to indicators in each scenario,and MARCOS method is used to sorting schemes.Finally,the optimal scheme for a hybrid energy storage system composed of Lithium Iron Phosphate Batteries(LFP)and Pumped Storage(PS)is obtained.Secondly,a two-stage collaborative optimization configuration model for hybrid energy storage systems is constructed.In the first stage,the high-frequency component of wind power output decomposed by CEEMDAN is regarded as the desired suppressed power of LFP.Then,the capacity configuration and operation optimization model of LFP is constructed with the goal of minimizing the total cost in the first stage.In this stage,the wind power for grid integration is obtained through optimization,which is the parameter of the model in the second stage.In the second stage,a two-layer capacity optimal configuration model of PS is constructed.The upper layer is configuration model,which configures the capacity and rated power of PS.The lower layer is operation optimization model,which optimizes the operation of the power system.The first stage model is solved by calling mature commercial solver.The upper layer of the second stage model is solved by an adaptive particle swarm optimization algorithm,and the lower layer calls CPLEX to solve after converting the nonlinear part into a linear form based on piecewise linearization method.Thirdly,the effectiveness of the proposed model is verified by numerical simulation.The LFP capacity configuration method based on CEEMDAN can reduce wind power fluctuation rate within 5min from 17.8%to less than 10%,which achieves the minimum LFP capacity configuration while making wind power fluctuations meet the technical requirements of grid-integration.After regulation by PS,the peak to valley ratio of load is reduced from 49%to 40%,and the wind power utilization rate of the system is 99.95%.In addition,the article sets up two comparative scenarios that only a single energy storage is constructed.The results show that if only PS is constructed,the fluctuation rate of wind power output exceeds 10%in 42 sampling times,and the maximum fluctuation rate is 17.7%,which also affect the economy of the second stage operation,resulting in a 21.57%increase in the total system cost.If only LFP is constructed,the wind power utilization rate reduces from 99.95%to 89.97%and loss-of-load occurs,resulting in a 16.43%increase in the total system cost.In addition,the sensitivity analysis results show that the investment cost of energy storage is a key factor affecting the wind power consumption rate and the total cost of the power system.The hybrid energy storage collaborative optimization configuration method proposed in this paper can effectively suppress wind power output fluctuations,reduce peak to valley differences,and promote the safe,stable,economic operation of power system.The innovation points of this paper are as follows:This article is based on the entire process of new energy grid integration,considering the problems caused by random fluctuations of renewable energy at different stages and time scales,and proposes a hybrid energy storage system collaborative optimization configuration method in new power systems.This method takes a large-scale wind power integrated system as an example,and the whole process of wind power grid integration is divided into two stages,in which two key issues are solved separately by optimizing configuration of hybrid energy storage system.This method achieves large-scale wind power grid integration,and promote the safety,stability and economic operation of power system after large-scale wind power integrated.Specifically:(1)Based on the characteristics of energy storage,a hybrid energy storage system selection model based on AHP-MARCOS method is proposed,and the energy storage selection in multiple scenarios of power system is completed;(2)An optimization strategy for wind power grid integration based on the CEEMDAN method is proposed,which minimizes the cost of VRB configuration while making the wind power fluctuation rate meet the technical requirements of grid-integration.A two-layer capacity configuration and operation optimization model of PS in large-scale wind power integrated system is proposed,which promotes the wind power utilization rate and improves the economy,safety and flexibility of system operation. |
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