Capacity Optimization And Economic Evaluation Of Grid-side And User-side Energy Storage System Based On Cooperative Game

In recent years,driven by China’s energy policy and market demand,the installed capacity of domestic electrochemical energy storage has increased rapidly,and the application of renewable energy grid connection,auxiliary services,power grid side and user side has grown significantly.The huge potential of battery energy storage in solving the power supply gap caused by the rapid increase of load in the regional distribution network makes the use of distributed grid-side and user-side energy storage to solve the problem of regional power distribution gap power supply become a future trend.Because the access of distributed energy storage has great effect on the voltage of the distribution network nodes and the loss of active power grid,and there is a dispute between the energy storage on the grid side and the energy storage on the user side.Therefore,it is necessary to conduct an in-depth study on the problems of grid-side distributed energy storage access to the distribution network in the regional distribution network and the optimization configuration of grid-side energy storage and user-side energy storage.The main research and results of this paper are as follows:(1)Research and analyze the source of incomes and costs structure of energy storage,and establish cost-benefit model of energy storage within battery life cycle.This paper first establishes the cost-benefit model of grid-side energy storage during the entire life cycle from five aspects: the income under time-of-use(TOU)electricity prices,the income of delaying grid upgrades after connecting grid-side energy storage to the distribution network,the income of electricity price subsidy from the government,energy storage recovery value,initial investment cost,and the operation and maintenance cost;then the cost-benefit model of user-side energy storage within battery life cycle was established from aspects of reducing the cost of user electricity bills,reducing the cost of electricity demand charge,government electricity subsidies,energy storage recovery value,initial investment cost,and the operation and maintenance cost;finally,the economics of grid-side energy storage and user-side energy storage are analyzed from three aspects of TOU electricity prices,battery cost,and government subsidized electricity price,and the battery selection of grid-side energy storage and user-side energy storage are analyzed.(2)Propose node comprehensive sensitivity coefficient and sequential placement strategy of multi-distributed energy storage.This paper first studies the issue of the connecting of DESS to distribution network,and analyzes the impacts on the system node voltage and active power loss after DESS connected to the distribution network;then,on the basis of active power loss sensitivity,considering the charge-discharge characteristic of energy storage,and the sensitivity of system node voltages and active power loss,node comprehensive sensitivity coefficient is proposed,and the rational analysis of the connecting of DESS to distribution network is conducted;for the issue of connecting multiple DESSs to the distribution network,fully considering the impacts of the connected DESS on the node voltage and active power loss,the sequential placement strategy of the multiple DESSs is proposed;finally,the advantages and disadvantages of configuration of DESS under active power loss sensitivity,node comprehensive sensitivity coefficient and the sequential placement strategy are compared and analyzed through calculation examples.(3)Introduce cooperative game theory to study the rational allocation of grid-side energy storage and user-side energy storage.This paper first analyzes the interests relationship between grid-side energy storage and user-side energy storage;second,based on the analysis of the basic elements of the cooperative game between grid-side and user-side energy storage alliance,the alliance maximum net profit is used as the objective function to establish the grid-side-user-side energy storage cooperative game optimization model;finally,an example is given to compare and analyze the the charge-discharge characteristic of energy storage and the overall economics of energy storage under two options of energy storage based on cooperative game method and single configuration of grid side energy storage.