Abstract This paper focuses on the refinement of the control strategy for grid-side energy storage systems as they engage in primary and secondary frequency modulation within an emerging smart grid. To attain an optimal outcome, traditional frequency modulation methods, which often require high-precision operations and extended adjustment periods, fall short of the stringent demands posed by modern power systems for swift and responsive frequency modulation. Under such circumstances, the grid-side energy storage control-terminal system presents a viable solution for managing energy storage, thereby providing rapid and precise assistance to the power system’s frequency modulation. By implementing a control mechanism that can adaptively switch between ARR signal-based and ACE signal-based frequency adjustments, a segmented parallel control approach ensures that the energy storage system can promptly and effectively modify the power within the grid system, facilitating swift frequency modulation.