Modeling and control strategy of battery energy storage system for primary frequency regulation

With large-scale integration of high penetration wind power, insufficient capacity problem of frequency regulation is getting increasingly prominent. Energy storage, with quick response characteristics, can meet the stability and reliability requirements of the grid when acted as a frequency regulation auxiliary means. First, based on the regional power grid and traditional generations' frequency regulation characteristics, the necessity for battery energy storage system (BESS) to participate in primary frequency regulation (PFR) was analyzed. Second, a BESS model applicable to primary frequency regulation simulation was built, and then sensitivity analysis for related key factors was conducted. On this basis, BESS participated in primary frequency regulation via using traditional droop control. And due to its inherent technical characteristics (energy restriction), this paper discussed three variable droop control strategies considering the state of charge (SOC) constraint, compared with the traditional fixed droop control strategy and thus summarized the applicable scenarios for these strategies. Finally, simulation verified the validity and reasonableness of the proposed strategies.