| With the large-scale renewable energy grid-connected,its fluctuating and power decoupling characteristics have caused renewable energy units to fail to provide sufficient frequency regulation reserve capacity.Due to the long start-up time and slow climbing speed of the traditional thermal power units,the frequency problems caused by the large-scale access of renewable energy sources cannot be adjusted quickly and in real time,causing great distress to the grid frequency.The energy storage system has the characteristics of accurate tracking,fast response,two-way adjustment,etc.,and is an effective means to maintain frequency stability.Because the adjustable power of the energy storage system is different in different states of charge,the power adjustment amount is insufficient in the case of the boundary value of the state of charge,resulting in a frequency that cannot be completely restored.Considering the output characteristics of energy storage,a controllable load is called on the load side for auxiliary adjustment.Therefore,from the perspective of source-load interaction,research on coordinated and optimized control of energy storage systems and flexible loads participating in automatic generation control of the power grid is of great significance in the study of large-scale renewable energy grid-connected power system frequency regulation.This paper first studies the frequency characteristics of a grid with a high proportion of new energy grid-connected,and analyzes the basic frequency response of the power system based on the measured frequency data.Use frequency data to analyze the frequency impact of new energy grid-connected on the power grid.By stabilizing the frequency fluctuations of the user side of the grid for one day,the frequency modulation demand analysis was conducted to explore the impact of a high percentage of new energy penetration on the system frequency.Secondly,the simulation model and control strategy of each auxiliary frequency regulation resource participating in automatic generation control are studied.A two-area interconnected power grid simulation system with thermal power generating units,energy storage systems and flexible loads participating in frequency regulation was established,and the improvement of frequency by different frequency adjustment resources participating in frequency regulation was studied.Coordinated control is based on the difference between the power-side regulation characteristics and the load-side regulation characteristics.Based on the frequency deviation division,an automatic energy storage control strategy that takes into account the interaction characteristics of source and charge is designed to provide a method basis for analyzing the relationship between energy storage types and frequency regulation efficiency evaluation.Then,the economic analysis method of the auxiliary frequency regulation of the battery energy storage system is designed,and the evaluation system of the energy storage efficiency of the battery to assist the frequency regulation of the integrated system is studied.A benefit,cost and penalty model for energy storage-assisted FM is established.The frequency regulation compensation mechanism that meets the balance of payments is analyzed.Developed a battery energy storage selection evaluation system that takes into account flexible load characteristics.Based on the frequency regulation efficiency index,energy storage technology index and frequency regulation economic index of energy storage applications,the four commonly used types of energy storage:lithium iron phosphate battery,lithium titanate battery,sodium sulffir battery and vanadium redox flow battery.Finally,the visualized experimental platform for integrated frequency regulation system is set up.In order to facilitate the research on the auxiliary frequency regulation characteristics of battery energy storage applied to a high percentage of new energy penetration grids,the GUI component design in MATLAB can be used to implement a user-oriented,integrated analysis and visualization visualization of a comprehensive frequency regulation system planning platform.Through the simulation experiment analysis,the effectiveness of the visualization experiment platform is verified. |
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