For improving the dynamic frequency and voltage stability of the large power grid after the connection of wind farm with high permeability to the system by different types of wind turbines

the chain type stage level static var generator（STATCOM-BESS）based on DC ring energy storage device

which possesses the ability to regulate the power operation in two-dimensional space

has been distributed widely in the wind farm. At the same time

the dual loop structure with damping control based on STACOM-BESS energy storage and concurrently power control can suppress the oscillation power of the system. Under this background

the ADRC（active disturbance rejection controller）with superior additional robustness is used to improve the stability of the grid connected system. Firstly

the controller of nonlinear self-identification disturbance factor principle is analyzed. Then

the control strategy of STATCOM-BESS to enhance the dynamic stability of the system is derived and analyzed with the method of damping torque and the additional damping controller is designed. The construction of 4-machine 2-area system of wind power grid connection is completed by the DIgSilent platform. The damping oscillation function of the additional control in the chain stage level STATCOM-BESS of DC loop energy storage device.