Abstract: A control strategy for hybrid energy storage-assisted thermal power units participating in primary frequency regulation was proposed to improve the frequency characteristics of a new power grid with a high proportion of new energy. Firstly, a primary frequency regulation model for thermal power-hybrid energy storage combined system considering the capacity degradation of energy-type energy storage was constructed. The frequency regulation dead zone of hybrid energy storage model was designed according to the frequency characteristics of power grid, and a local inertia compensation control strategy was proposed. On this basis, the model predictive control for primary frequency regulation of thermal power-hybrid energy storage combined system was implemented based on the prediction of load disturbances and system state variables, and rolling optimization was performed on the output regulation parameters of coal-fired units and various energy storage systems. Simulation results show that the proposed control strategy can effectively reduce the dynamic and steady-state frequency deviations of the system, decrease the output adjustment frequency of units and the charge-discharge depth of lithium batteries, and improve the power grid frequency quality. Compared with the traditional droop control, the amplitudes of the maximum dynamic frequency deviation and steady-state frequency deviation under step disturbance are reduced by 6.8% and 5.8% respectively, the root-mean-square frequency deviations under continuous disturbance and long-term disturbance are reduced by 8.2% and 7.2% respectively, and the percentages of frequency out-of-limit time are reduced by 10.5% and 16.1% respectively.