Research On Collaborative Optimization Strategy Of Distributed Energy Storage System Aggregating To Participate In The Frequency Modulation

Energy storage has the function of storage,fast response speed and high climbing rate.It can effectively improve the power quality of the power grid under the scenario of high renewable energy permeability.It is an important component of building a clean,low-carbon,safe and efficient energy system and a new power system with new energy as the main power supply.Distributed energy storage is an important part of it,which is large in quantity and widely distributed.However,the current distributed energy storage application scenarios are single,the utilization rate is low.besides,the out-of-order access of massive distributed energy storage will bring more challenges to the stability of the power grid.If the small,scattered and disordered idle capacity of distributed energy storage can be gathered together to form a large,concentrated and orderly cluster to participate in auxiliary service of power grid through effective collaborative optimization strategy,the utilization rate of energy storage resources will be effectively improved,the development of distributed renewable energy will be promoted,the "30·60" carbon peak carbon neutrality goal will be easier to achieve.This paper focuses on the user-side distributed energy storage,makes full use of the complementary characteristics of the spare capacity of distributed energy storage,and studies the aggregation and collaboration strategy based on the State Based Potential Game(SPG)theory,so as to form a certain scale energy storage cluster to participate in the auxiliary service of power grid frequency modulation.Following work has been completed:(1)A state potential game model of aggregating distributed energy storage to participate in frequency modulation auxiliary services is established.This part firstly decouples the global linear coupling constrain in the frequency modulation problem into the local constraints of each energy storage by introducing estimation state.Then the potential function is constructed to achieve the consistency of the benefits of power system and distributed energy storage individual.By two steps mentioned aboved,the problem of how to aggregate distributed energy storage to participate in frequency modulation service is transfromed into a state based potential game,by which the research on collaborative optimization strategy is easier to start.(2)Research on collaborative optimization strategy of primary frequency modulation considering distributed energy storage aggregation.This part mainly focuses on the problem of insufficient unit regulated power in the case of high renewable energy penetration,and proposes a strategy to improve unit regulated power of the power grid by aggregating distributed energy storage.Through the design of distributed energy storage communication mechanism and the state transition function,this strategy can make the distributed energy storage cluster,in adapt to the part of individual random access/exit case,dynamically trackes the given unit regulated power,thus providing stable additional unit regulated power to enhances the frequency stability of the power grid.(3)Research on secondary frequency modulation collaborative optimization strategy with energy storage participation.In this part,a dynamic AGC signal allocation strategy is designed,considering the scenario where distributed energy storage and conventional units participate in the secondary frequency modulation together.In this strategy,the dynamic distribution of AGC signals is completed by the collaborative process of frequency modulation units.By fully considering local constraints such as climb rate and state of charge(SOC)of frequency modulation units,the strategy can accurately track AGC signals and dynamically allocate frequency modulation responsibilities.In addition,the real-time frequency modulation capability of energy storage with different technical characteristics can be quantitatively evaluated by setting the frequency modulation cost function which takes into account the frequency modulation mileage and the storage state of charge.