The Suppression Measures Of Synchronous Oscillation Of The Offshore Wind Farm In AC Transmission

As the proportion of wind turbines in the power generation market continues to increase,the threat of sub-synchronous oscillation brought by the grid connection of large-scale wind farms cannot be ignored.Some commonly used reactive power compensation equipment in the system may cause or even exacerbate the sub-synchronization of the system.It is necessary to propose practical strategies to improve the stability of doubly-fed wind farms in the face of subsynchronous oscillation accidents.Therefore,the main work of this paper includes:1)The research status of subsynchronous oscillation of doubly-fed wind turbines is introduced,and the mathematical model of doubly-fed wind turbines is established.Matlab simulation software is used to build a simulation model with reference to the actual case of subsynchronous oscillation accident in Hornsea wind farm.The subsynchronous oscillation phenomenon of the Hornsea wind farm is reproduced,which provides a simulation basis for subsequent research.2)It is proposed to replace the voltage PI control module of the static var compensator with a linear active disturbance rejection controller to estimate and compensate the total disturbance in the Hornsea wind power system,overcome the contradiction between the system response speed and overshoot,and improve the system Stability and robustness,suppress the subsynchronous oscillation phenomenon of wind power system.3)Based on the linear active disturbance rejection control and positive sequence voltage component compensation technology,the control strategies of the rotor-side converter and grid-side converter of the doubly-fed wind turbine are respectively improved.On the one hand,the grid-side converter is used to output reactive power to support the rapid recovery of grid voltage,The stability of the system is improved.On the other hand,the influence of the subsynchronous disturbance on the wind turbine is offset by the rotor-side linear active disturbance rejection controller,and the disturbance resistance and robustness of the system are improved.The simulation results verify the effectiveness of the proposed control strategy in suppressing the subsynchronous oscillation of the weak AC wind power system after it is applied to the DFIG system,which can provide a reference for the study of similar problems of offshore wind power grid connection in my country.The simulation results verify the effectiveness of the proposed strategy in suppressing subsynchronous oscillation of the weak AC wind power system after the application of the weak grid doubly-fed offshore wind farm,which serves as a reference for studying similar problems of offshore wind power in China.