Abstract: In this paper, the LCL coupled static synchronous compensator（STATCOM） is introduced to solve power quality problems such as voltage fluctuation and harmonic pollution caused by the distributed wind power connected to the power grid. In view of the particularity of nonlinear timevarying system and the improvement of device compensation performance,the dual-loop control of the LCL-type STATCOM is proposed based on the transition process of the coupling point voltage outer loop nonlinear PI and current inner loop quasiproportional resonance（QPR）cascade. The transition process is used to reduce the initial error of signal,reduce the overshoot and accelerate the response rate. Through the analysis of frequency characteristics,the parameters of the QPR controller suitable for the system are designed. In order to verify the effectiveness of the proposed control strategy,a simulation model is built through MATLAB/SIMULINK platform,and the voltage fluctuation suppression and harmonic control effects of the device under the dual-PI control strategy are compared and analyzed. The simulation results show that the control strategy has better suppression effect on the voltage fluctuation and current distortion rate of the system,and can effectively improve the stability and power quality of the system.