The moment of inertia of synchronous machine plays a key role to maintain system stability.With the ever increase of direct current in-feed capacity and new-energy installation capacities in Jiangsu province

the traditional synchronous generators will be replaced gradually.At the same time

the inertia of Jiangsu power grid will be reduced remarkably

which will have major and complex impact on the safety and stability of the system.Introduction of virtual inertia through power electronic equipment is the effective method to enhance the grid frequency stability.Variable-speed wind turbines with doubly-fed induction motors can perform decoupling control of its active and reactive power decoupled control respectively and has the advantages of flexible control and fast response.By adding the additional control to the fan of the wind turbine

power generated by the wind turbine can be controlled to release the kinetic energy stored in the fan impeller and rotor shafting and participate in the regulation of the system frequency stability.Firstly

influence of inertia reduction to the frequency stability in Jiangsu power grid is analyzed briefly in this paper from the point of view of frequency stability.Then

the way to realize virtual inertia control of the wind turbine is analyzed specifically.Finally

the influence of virtual inertia control on frequency stability of Jiangsu power grid by the use of large scale of wind turbine is summarized through examples of simulation.