Study On Balancing Power Fluctuations Of Energy Local Network Tie-line Considering "Wind-Storage-Load"

Combined with renewable energy technology and information technology,Energy Local Network(ELN)is committed to promoting the large-scale use and sharing of distributed renewable energy,to achieve changes in energy use patterns.In the energy distribution network,the wind power as the representative of the renewable energy power generation have the characteristics of random,intermittent and so on,which leads to its power fluctuations causing a certain risk on the operation of the ELN,and causes damage to the operation of the distribution system.Generally there need to be equipped with a special energy storage device to stabilize the power fluctuations from the ELN.However,the cost of a separate energy storage device is too high to match the economic operation of ELN.Therefore,technical and market-oriented means is needed to avoid ELN power fluctuations,reduce the operating costs of ELN,and promote the large-scale use of distributed renewable energy.In view of the risk of power fluctuation caused by wind power and load uncertainty in ELN,this paper puts forward the insurance strategy to avoid the operational risk.The significance of insurance lies in the transformation of uncertain small probability of large risk losses into deterministic small financial expenditures and the elimination of huge economic losses by sacrificing acceptable economies.First of all,the unbalanced electricity price is introduced to balance the unbalanced cost caused by the power fluctuation of the ELN tie line,then sample the wind power output among various scheduling time by virtue of the Monte Carlo simulation,further more,calculate the unbalanced cost expectations and standard deviation,in order to determine the insurance premiums of purchased insurance.The coordination model of insurance and energy storage is constructed,taking the minimum cost of insurance and storage cost as the target,the capacity of energy storage device is the decision variable,and the global optimal solution of storage capacity and premium cost is obtained.The concept of the starting value of the insurance is introduced,When the imbalance cost caused by the power fluctuation of the ELN tie line is greater than the starting value of the insurance,the insurance claim is adopted to transfer the loss,thereby ensuring the economic operation of the energy ELN.When the imbalance cost caused by the power fluctuation of the ELN tie line is less than the starting value of the insurance,charging and discharging device by the energy storage is to stabilize the power fluctuation of tie line,the insurance company also to avoid the small probability of risk loss accident claims.The simulation results show that the effectiveness of the strategy,which provides a theoretical basis for the economic operation of ELN.Considering the characteristics of the mobile storage of electric vehicles in theELA,the power fluctuation of the tie line can be stabilized by arranging the charging and discharging time of the electric vehicle reasonably.Therefore,the construction of a two-tier optimization model that can simultaneously achieve a win-win situation between ELN and electric vehicle operators:In the upper optimization model,by optimizing the charge and discharge prices of electric vehicle operators in each period,so that maxmize the income and minimize the risk loss of ELN in the study time interval.In the lower optimization model,according to the charge and discharge price given by ELN,the electric vehicle operator make a optimal management to the charge and discharge time of electric vehicle under their jurisdiction,so that minimize the operating costs of the electric vehicle operators.In addition,measure the loss of risk in the market trade process of ELN with CVaR,this paper analyzes the charging and discharging price strategy of energy local area network with different risk preference,and the influence of risk preference and the number of electric vehicles involved in dispatching on the expected income and expected risk loss of ELN.Finally,the validity of the proposed model and method is verified by calculation and analysis.