Study on Sub-Synchronous Oscillations of Power Systems Caused by Grid-Connected Wind Farms Based on the Improved Complex Torque Coefficients Method
Wang Yijun1, Du Wenjuan2, Chen Chen1, Wang Haifeng1,2
1. State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing 102206 China; 2. College of Electrical Engineering Sichuan University Chengdu 610065 China
Abstract To examine the torsional sub-synchronous oscillations of power system systems caused by the dynamic interactions between grid-connected wind farms and synchronous units, this paper establishes a multi-input and multi-output closed-loop interconnect system model, which divides the system into synchronous machine subsystem and wind farm subsystem. On the basis of pointing out the defects of the traditional complex torque coefficients method, an improved complex torque coefficients method based on eigenvalue sensitivity is proposed. The effects of the variation of steady-state flow and dynamic interactions introduced by integration of wind farms are considered. Finally, the effectiveness of the proposed method in a single-machine and a multi-machine power system with grid-connected wind farms is verified by simulation analysis. From the perspective of damping mechanism, the near strong modal resonance phenomenon between the synchronous machine shaft system and the DFIG wind farm is explained. The influence of the control parameters of the VSC, the load of the transmission system and the level of the dynamic interactions on the near strong modal resonance between the shaft system of synchronous generators and control system of the wind farms are analyzed.
Wang Yijun,Du Wenjuan,Chen Chen等. Study on Sub-Synchronous Oscillations of Power Systems Caused by Grid-Connected Wind Farms Based on the Improved Complex Torque Coefficients Method[J]. Transactions of China Electrotechnical Society, 2020, 35(15): 3258-3269.
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2020, Vol. 35 
