Due to the large-scale application of energy storage auxiliary conventional units in frequency modulation in power system

it is the key problem in energy storage frequency modulation how to develop reasonable energy storage output control strategy to achieve complementary operation of energy storage and conventional units. On the basis of real-time state perception and comprehensive evaluation

the control strategy of two kinds of operation conditions of energy storage(adaptive frequency regulation and restoration of the state of charge(SOC))is established

using Logistic regression model. The area control error(ACE)signal is divided into different intervals to quantitatively describe the spare capacity of secondary frequency regulation of the conventional power units. Then the output goals of energy storage in different ACE intervals are set up

which are determined by the comprehensive consideration of the ability of frequency regulation and the SOC recovery demand. Therefore

the energy storage and the conventional units can participate in the secondary frequency regulation in a coordinated way. Finally

two typical scenes are constructed in MATLAB/Simulink

and the proposed control strategy is simulated and verified. The simulation results show that the proposed control strategy has advantages in improving the effect of frequency regulation

maintaining the SOC of energy storage

and achieving better utilization of the conventional units.