Research On Siting And Sizing Of Energy Storage In Distribution Network Considering Four-quadrant Power Operation Strategy

In recent years,distributed generation has brought many challenges to the distribution network.The fluctuation and randomness of the distributed photovoltaic with high penetration will seriously affect the voltage quality of the distribution network,such as out of voltage limit and violent voltage fluctuation.This paper proposes to introduce the four-quadrant power operation strategy of the energy storage system using the advantages of high energy density and rapid charge and discharge of the battery energy storage system to provide significant ideas to solve the above problems,the location,installation capacity and real-time charge-discharge power of the energy storage system have an impact on the voltage quality and economic benefits of the distribution network.Therefore,this paper studies the siting and sizing of the energy storage system in the distribution network.First,this paper introduces the development of inverter with four-quadrant power operation and energy storage technology,the research status of energy storage participating in improving voltage quality and economy,as well as the research status of energy storage siting and sizing,and briefly expounds principle of energy storage inverter with four-quadrant power operation,taking the simple distribution network line and load model as an example,quantitatively deducing and analyzing the influence of energy storage system on the distribution network voltage distribution and network loss.The derivation formula shows that siting and sizing of energy storage system have a great influence on the distribution network,and the influence of active and reactive power on the voltage and network loss of the distribution network is equivalent.Secondly,in view of the operation strategy of energy storage system,combining with the dispatching instructions,the four-quadrant power operation strategy of the energy storage system is proposed.Starting with the structure and operation principle of the three-phase energy storage inverter,the four-quadrant power operation control method is studied and analyzed,and based on the control strategy,the grid-connected model of the three-phase energy storage inverter is built on the Matlab/Simulink platform.Simulation results show that the energy storage system has fast,efficient and stable four-quadrant power output capacity.Finally,based on the economic operation modeling of the distribution network,the optimal allocation strategy of energy storage is put forward combined with the power four-quadrant output control strategy of the battery energy storage system,which is in view of the interests of distribution network operators,consider the allocation of energy storage to improve the voltage quality,while maximizing the economic benefits of distribution network operation.Specifically,an economic operation model for distribution network with the goal of minimizing the sum of purchase cost,network loss cost and investment cost is constructed.15 min is used as time scale for rolling calculation,and the lowest total cost in a typical day is used to choose the siting and sizing of storage.Meanwhile,the migration and fluctuation range of each node voltage is constrained,and the mixed integer second-order cone mathematical programming is used to optimize the solution for the non-convexity of the model.Taking IEEE 33 node distribution network and historical data of typical day as an example,the feasibility and efficiency of the proposed optimal configuration method are proved.The results show that the energy storage system,with its ability of fast and efficient four-quadrant power output,using the time-sharing electricity price mechanism to realize the arbitrage,which improves the economy of power purchase by the superior power grid.Besides,the excessive voltage offset is adjusted and the excessive fluctuation of the node voltage caused by the photovoltaic output is reduced,and the power quality of the distribution network is improved.In the meanwhile,the network loss is fully reduced and the power loss of the distribution network is reduced.