The large-scale integration of renewable energy sources leads to significant fluctuations in the grid frequency. Coal-fired power plants have relatively low flexibility. Energy storage can enhance their regulation capabilities

which is of great significance for actively supporting the stability of the grid frequency. The power grid adopts the paid frequency regulation mode of automatic generation control (AGC)

which features high frequency and continuous reversal. This paper clusters the AGC instructions of the power grid

takes into account the advantages of flywheel/lithium battery hybrid energy storage technology

and proposes a hybrid energy storage-assisted AGC control strategy for thermal power plants based on mode matching. It dynamically adjusts the state of charge of the energy storage

quantifies the relationship between the hybrid energy storage of flywheel/lithium battery and the improvement of the single frequency regulation performance index of the unit

and adaptively coordinates the output power and time nodes of the three. The results show that compared with the conventional control strategy

the average kp value of the proposed strategy is increased by 19.98% per day

and the daily regulation depth is increased by 166 MW. It has also been applied to a unit in China

with the kp value increased to 4.70

and the average daily cycling times of lithium batteries decreased by 34.27%

achieving limit regulation of the total power ratio of the energy storage system below 3% of the unit capacity.