Wind turbines participation in system frequency regulation is aimed at improving the deterioration of frequency dynamic response characteristics caused by a large-scale integration of new energy into the power system. However

the contradiction between traditional virtual inertia control and the inherent speed controller of wind turbines weakens the frequency regulation ability of the virtual inertia control of wind turbines

and the inertia and damping requirements of the system are not considered in the frequency regulation process. Therefore

an optimal control strategy for virtual inertia of wind turbines is proposed in this paper. Firstly

the frequency response model of the power system with virtual inertia control of wind turbines is established

and the frequency response characteristics of the system are quantified by studying the frequency regulation mechanism of the interactive system

and the frequency change rate of the system and the maximum safe range of the frequency deviation are described. Secondly

based on the safe and stable operating conditions of the wind turbines

a constraint function is established for the output electromagnetic power of the wind turbines and the release of rotor kinetic energy. Then

in order to solve the contradiction between the inherent controller and the virtual inertia control of the wind turbines

a virtual inertia optimization control scheme for the wind turbines is proposed. Based on the inertia and damping requirements of the system and the constraints of safe and stable operation of the system and the wind turbines

the key coefficients of the virtual inertia optimization control are adjusted. Finally

we use PSCAD/EMTDC software to establish a primary frequency regulation model of the system with virtual inertia optimization control of the wind turbines

and verify the accuracy and effectiveness of the proposed optimization control scheme.