Study On Wind Power Grid-connected Primary Frequency Modulation With Hybrid Energy Storage System

As the penetration rate of wind power in power systems continues to increase,the integration of large-scale wind power into the grid will reduce the inertia of the system.Due to the volatility and uncertainty of wind power,the frequency stability of the system will bring no small challenge.The addition of the energy storage system can effectively improve the frequency stability of the wind power grid-connected system,and the hybrid energy storage system can overcome the limitations of a single energy storage system and has superior performance.In this paper,the frequency stability problem caused by large-scale wind power grid-connected is analyzed.The influence of load change and wind power grid-connected on system frequency is analyzed.The scheme of hybrid energy storage system participating in primary frequency modulation is proposed,and the hybrid energy storage system is applied to the system.The control strategy of hybrid energy storage system is studied for system frequency adjustment.The research content of this paper can provide reference for the research of hybrid energy storage system participating in system frequency modulation,which has certain feasibility and engineering application value.The main research contents and results of this paper are as follows:(1)By studying the influencing factors of power system frequency stability,a simplified power system model and a doubly-fed wind turbine model are established to simulate load changes,generator parameter changes,and system frequencies after different numbers of wind turbines enter the system.influences.By observing the curve of system frequency with time,the degree of influence on system frequency under different factors is analyzed and compared.The results show that the missing inertia weakens the anti-interference ability of the system when the fan that is integrated into the grid increases.A hybrid energy storage system is used to participate in the process of frequency modulation.(2)The hybrid energy storage system consists of a superconducting magnetic energy storage system and a battery energy storage system,so that the two respectively bear the high frequency and low frequency parts of the command power,and design a double control structure of the central control unit and the local control unit,thereby Achieve control of the hybrid energy storage system.The model of the energy storage system was built and simulated in Matlab/Simulink.The results show that accessing the hybrid energy storage system can restore the frequency to a normal working level faster.(3)Controlling the inertial response and droop response of the frequency respectively,and proposing an energy storage system control strategy based on IR-PFR.The simulation results show that the energy storage system can effectively compensate the large-scale wind power integration after participating in the system.And the impact of load changes on the frequency,so that the system has better dynamic performance and anti-interference ability.