Research on the Sub-synchronous Oscillation Optimization Control Technology of Doubly-Fed Wind Turbine Based on Genetic Algorithm

The sub-synchronous oscillation accident of large-scale doubly fed wind turbines connected to a grid through series compensation has caused a serious impact on the power system. By optimizing the parameters of the doubly fed fan control system, the system impedance can be effectively improved to solve the problem of sub-synchronous oscillation. However, owing to the complexity of a grid-connected system of doubly fed fans and the influence of the time-varying oscillation characteristics of the system, it is often difficult to achieve a successful suppression. To solve this problem, this paper proposes an optimized additional damping method for the rotor and grid-side controllers, which can achieve efficient suppression of sub-synchronous oscillation. The parameters of the proposed additional damping method are optimized for all variable operation conditions using a genetic algorithm under the established frequency-domain impedance model. The detailed time-domain simulation model was constructed with the RTLAB platform to verify the proposed method. The experimental results show that the optimized control strategy can effectively and quickly suppress the sub-synchronous oscillation under different working conditions, and the amplitude suppression rate reached 85.99%, which effectively improved the grid-connected stability of wind turbines.