Journal of Shanghai Jiao Tong University ›› 2023, Vol. 57 ›› Issue (9): 1156-1164.doi: 10.16183/j.cnki.jsjtu.2022.135

Special Issue: 《上海交通大学学报》2023年“新型电力系统与综合能源”专题

• New Type Power System and the Integrated Energy • Previous Articles     Next Articles

An Adaptive Additional Control Strategy for Suppressing Low-Frequency Grid Oscillations in Doubly-Fed Wind Farms

LIU Xinyu1(), WANG Sen1, ZENG Long2, YUAN Shaoheng1, HAO Zhenghang3, LU Xinyan1   

  1. 1. School of Electric Power, North China University of Water Resources and Electric Power, Zhengzhou 450011, China
    2. School of Automation, Guangdong University of Technology, Guangzhou 510006, China
    3. The Electrical Engineering College, Guizhou University, Guiyang 550025, China
  • Received:2022-05-03 Revised:2022-06-28 Accepted:2022-11-28 Online:2023-09-28 Published:2023-09-27

Abstract:

Aiming at the problem of weakly or negatively damped low-frequency oscillations caused by cross-zone transmission of electricity from large wind farms, this paper proposes a fast terminal sliding-mode additional damping controller based on the Lyapunov stability theory. By investigating the flexible power regulation characteristics and the capability of dynamic frequency response to damping regulation of doubly-fed wind turbines (DFIG), a rotor magnetic chain controller is designed according to the relationship between the applied voltage and magnetic chain of DFIG rotor and the sliding mode variable structure control method. When low-frequency oscillations occur in the system, the desired magnetic chain value will deviate from the actual magnetic chain value. The additional damping controller outputs an adaptive control signal for the rotor-side power control link to increase the active output of the wind farm and suppress low-frequency oscillations in the system. A simulation model of the wind power grid-connected system is established in MATLAB/Simulink for off-line simulations, and a real-time simulation experiment of a large wind farm cross-zone transmission model based on real time digital simulation system is conducted. The results of both off-line and real-time simulations show that when low-frequency oscillations occur in the system, the proposed control method can quickly regulate the active power emitted by the DFIG and enhance the damping level of the system, which is effective in suppressing low-frequency oscillations in the system.

Key words: doubly-fed wind turbines (DFIG), frequency stability, low-frequency oscillation, Lyapunov stability, sliding mode control

CLC Number: