As more and more unconventional energy sources enter the field of power generation

the frequency fluctuation of power system becomes more and more serious. The frequency modulation of thermal power units has disadvantages such as long response time and slow climbing speed. Battery energy storage has gradually become a research hotspot in power system frequency modulation due to its quick response and flexible regulation. This article introduces two basic modes of energy storage participating in power system secondary frequency regulation

namely the regional control deviation and regional control demand

and analyzes the characteristics of these two basic control modes. The area control deviation and the state of charge(Ssoc) of the battery in the energy storage system are divided into different areas. Considering the frequency regulation demand and the output characteristics of the energy storage system in different areas

different frequency modulation methods are proposed. Under the normal adjustment of the regional control deviation and the normal charging and discharging state of the Ssoc

the fuzzy controller is used to smooth the output of the energy storage system. Finally

the two-area interconnected simulation system is established based on MATLAB/Simulink simulation platform

the simulation results show the effectiveness of the proposed control strategies.