Researches On Battery Energy Storage Participates In Power Grid Frequency Regulation With Pumped Storage

As the permeability of renewable energy power generation systems increased year by year,their inherent randomness and volatility brought many challenges to the stable operation of power systems.Due to the long response time and low ramp rate,conventional power supplies cannot fully meet the requirements of new energy access.Therefore,it is particularly important to equip the future grid with reasonable energy storage equipment to ensure the flexibility of renewable energy utilization and the flexibility of the power system.In this context,various types of energy storage technologies have been rapidly developed and pumped storage is the most widely used among them.In summer and winter,the electricity load is relatively tight.The pumped storage is mainly used to adjust the peak load to relieve the pressure of the conventional units.However,in spring and autumn,the demand for electricity is not too much and the peak adjustment pressure is relatively small.The pumped storage can be used as a high-quality frequency modulation resource to assist the thermal power plant to participate in the system frequency modulation.But if the pumped-storage power plant is used as the main frequency-control power plant,it need to configure pumped storage enough spare capacity,which will lead to unsatisfactory economic benefits.Therefore,it may be considered to use the battery energy storage as a supplement for frequency modulation,it can improve the effectiveness of frequency modulation and ensure the economic benefits of it.This paper focuses on the problem of battery energy storage participating in grid frequency regulation with pumped storage,and studies the question of theoretical methods and techniques of working principle,system modeling,model simulation,capacity allocation,and economic evaluation.First,the paper systematically discusses the basic principles of primary and secondary frequency modulation in power systems,and the model of the conventional unit frequency modulation element is constructed;based on this,the single-zone and two-area load frequency control model is constructed;by analyzing the influence of the nonlinear link on the load frequency control,a two-area load frequency control model considering nonlinear factors is constructed.based on the operating characteristics of pumped-storage units and the establishment of pumped-storage unit model under power generation and pumping conditions respectively,a two-region load frequency control model with pumped-storage units under non-linear linking power generation and pumping conditions is constructed,and these models are tested by simulation.Secondly,the feasibility and necessity of battery energy storage in the frequency modulation of pumped-storage power grid are analyzed.The dominant characteristic parameters of battery energy storage in power system frequency modulation is described,and the new battery energy storage equivalent model based on battery energy storage monomer is constructed.On the basis of the two-area load frequency control model with pumped storage,a two-area load frequency control model with battery energy storage involved in pumped storage is constructed,and the model is tested by simulation.Finally,in the light of the empirical mode decomposition technology,the power and capacity configuration methods for battery energy storage and pumped storage power are described respectively,and the technical and economic evaluation indicators for these two types of energy storage to participate in grid frequency regulation are constructed.The battery storage based on the full life cycle theory is constructed,and an evaluation model of pumped storage frequency modulation benefit based on the equivalent substitution method is constructed;according to the ACE signal in the power grid,the index of mixed energy storage participation in secondary frequency modulation is defined;the capacity of the hybrid energy storage is configured with the goal of optimal frequency modulation effect and economy.According to the results of the simulation,the configuration and operation control method of this paper can be made economic evaluation,and it provides a reference for the practical application of this method.