Primary FM Control Strategy for Energy Storage Considering Multiple Storage Links

Aiming at the problem of frequency fluctuation of new energy-enriched power system and the joint participation of multiple energy storage links in grid FM, this paper introduces two battery energy storage links to participate in realizing grid FM, and proposes a control strategy of battery energy storage assisting thermal power units to participate in primary grid FM. Based on the premise of the impact of real-time changes in the state of charge (SOC) of battery storage systems in the frequency modulation (FM) process under different dead zones on the FM capability of the whole grid, combined with the sag control method of thermal power units, a logistic form function is introduced into the primary FM model of the grid, which realizes that the battery storage system can be dynamically controlled by the thermal power units in the FM process under different dead zone sizes. The control strategy of the battery energy storage system can simulate the grid participation in primary FM with the assistance of thermal power units under different dead zone sizes using dynamic sagging. Compared with the previous fixed-sag control method, this strategy has a lower frequency deterioration rate and root-mean-square (RMS) value of frequency and better frequency regulation results.