| With the proposal of China ’s "double carbon target," the energy and power industry has begun to accelerate the development of new energy.It is proposed to build a new power system with new energy as the main body and build a low-carbon,clean and efficient energy system.With increasing wind power,and the rotor of the wind turbine is decoupled from the grid frequency,the frequency fluctuation of the power system is becoming more and more serious.Flywheel energy storage has the characteristics of no regular maintenance,no pollution,long life and high cycle efficiency.It is very suitable for short-term fast charging and discharging application scenarios.Therefore,flywheel energy storage system can effectively improve the output characteristics of wind power and contribute to solving the problem of large-scale wind power integration.This paper mainly studies the following three aspects in the power system with wind power by using flywheel energy storage technology to assist grid frequency modulation and improve frequency quality:Abstract(1)Analysis of frequency modulation characteristics of flywheel energy storage:Aiming at the performance of flywheel energy storage and electrochemical energy storage,through the establishment of model comparison and analysis,it is shown that flywheel energy storage is more responsive than electrochemical energy storage;after that,the substitution effect of flywheel energy storage on frequency modulation of thermal power units is studied.By defining the substitution effect of flywheel energy storage and thermal power units with the same power and the substitution index of the two under the same frequency index,the regional power grid model is established to verify the high substitution ability of flywheel energy storage frequency modulation to thermal power unit frequency modulation when the same disturbance of power load occurs.(2)Simulation analysis of flywheel energy storage assisted wind power primary frequency regulation:The primary frequency regulation model of flywheel energy storage assisted large-scale wind power grid-connected system is established,and the frequency response characteristics of primary frequency regulation without flywheel energy storage,using wind power frequency regulation and containing flywheel energy storage frequency regulation are analyzed.Through the simulation of step load disturbance and continuous load disturbance,the frequency results under these three different conditions are compared,which shows that the primary frequency modulation assisted by flywheel energy storage can significantly improve the performance of primary frequency modulation.Finally,in order to better improve the frequency modulation effect,the frequency modulation effect of fuzzy control and droop-inertia control is compared and analyzed,which shows that fuzzy control can improve the frequency modulation effect more effectively.(3)Simulation analysis of secondary frequency regulation of wind power assisted by flywheel energy storage:The problem of secondary frequency regulation in the operation of two-area interconnected power system with high proportion of wind power is studied.In the scenario where the frequency regulation ability of power system with wind power is weak,a two-area interconnected power system model with turbine generator,wind power and flywheel energy storage is established.The frequency response characteristics of the system without energy storage and the interconnected power system with flywheel energy storage in secondary frequency regulation are analyzed.Through simulation research,the use of flywheel energy storage auxiliary power grid for secondary frequency modulation can significantly improve the frequency stability of the system and further control the frequency deviation of the interconnected power system. |
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