Optimal Dispatch And Capacity Allocation Of Distributed Energy Storage In Distribution Networks With DG And EV

With the increasing access proportion of distributed generation(DG)and electric vehicles(EV)in the distribution network,the problem of transformer overload and DG consumption in the distribution network has attracted more and more attention.Simply relying on the expansion and upgrading of transformer,the utilization rate of distribution equipment is low,the investment economy is poor,and it is not conducive to the consumption of DG.Distributed energy storage(DES)has two-way energy transfer function,which is an important means to reduce transformer load rate and improve DG consumption.Distributed energy storage(DES)has a bidirectional energy transfer function,which is an important means to reduce trantsformer load rate and improve DG consumption.The quality of the DES control strategy affects its operating results,and the related capacity allocation has a greater impact on its investment economy.Therefore,for the distribution network with DG/EV,the research on the optimal control and capacity allocation of distributed energy storage is a hot topic at present.This paper first considers the access of DG and EV,proposes a typical distribution network structure with DG/EV/DES,and establishes the upper network power supply load model to analyze the impact of DG and EV on the distribution network.The DG,EV,DES and other devices in the distribution network are modeled,and the characteristics of each model are analyzed.Considering the extreme output of Dq the demand of DES is analyzed according to the change of the supply load,which provides theoretical basis for the development of DES control strategy.Then briefly describe the principle and method of the original constant power control strategy.In view of the low economical characteristics of constant power control strategies,in order to improve the economics of energy storage operations,a DES economic operation mechanism is proposed,including DES economic arbitrage and loss reduction mechanisms.Establish a DES economic dispatch model based on the proposed DES economic operation mechanism.Established evaluation indicators to compare the advantages and disadvantages of the two control strategies,providing a method foundation for the optimized configuration of DES capacity.Finally,according to the demand of transformer overload,the demand analysis of energy storage capacity is carried out,and the corresponding relationship between different energy storage capacity and the capacity expansion of transformer is analyzed.Considering the limitations of the original site selection method based on load peak network loss sensitivity,a DES site selection method based on the standard deviation of network loss sensitivity is proposed.Considering the investment cost,operation and maintenance cost of DES,as well as the cost of transformer expansion,the benefit of deferring the expansion of transformer,the benefit of network loss,arbitrage benefit,environmental benefit and other factors,aiming at the minimum net cost of coordinated planning,a coordinated planning model of DES capacity allocation and transformer expansion is established.A solution method of coordinated planning model is proposed,which can greatly reduce the net investment cost and improve the economy of energy storage allocation.