An Enhanced Frequency Response Strategy of a DFIG Based on Over-Speed De-Loaded Curve

Abstract

The increasing level of wind power penetration is seriously threatening the frequency stability of the power system. In this article, we suggest an enhanced frequency response strategy of a doubly fed induction generator (DFIG) based on over-speed de-loaded curve using a novel power function to boost the frequency nadir and settling frequency and reduce the maximum rate of change of frequency (ROCOF) with more efficiency. To achieve this objective, the reference power increases to the torque limit at the de-load operating point and then decreases with the rotor speed toward the maximum power point tracking operating conditions. The simulation results on various wind power penetrations clearly demonstrated that the enhanced frequency response strategy is beneficial to boosting the frequency nadir and settling frequency and reduce the ROCOF.

Supplemental Control for System Frequency Support of DFIG-Based Wind Turbines

“…Thus, it has a high cost. In [11], an improved method of a DFIG based on the over-speed and deloaded curve was introduced to reduce the ROCOF. A synergistic control strategy was proposed in [12] considering mechanical stresses on the equipment associated with the pitch angle controller and its slow response speed.…”