https://doi.org/10.1177/0309524X18780385 Wind Engineering 1–19 © The Author(s) 2018 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0309524X18780385 journals.sagepub.com/home/wie Coordinated reactive power and crow bar control for DFIG-based wind turbines for power oscillation damping Likin Simon 1 , Jayashri Ravishankar 2 and K Shanti Swarup 1 Abstract The fault ride through capability and fast controller action makes doubly fed induction generator based wind energy conversion system to actively participate in power oscillation damping. This article describes a coordinated reactive power control from grid side converter along with active crowbar scheme for doubly fed induction generator which can actively participate in power oscillation damping, and thus improve the transient stability margin of entire power system. For a reactive power oscillation damping (∆Q power oscillation damping), it is essential that the phase of the modulated output is tightly controlled to achieve a positive damping. Detailed 3 generator 9 bus Western System Coordinating Council system is modeled in PSCAD/EMTDC with the generator dynamics. The dynamics in power flows generator rotor speeds and voltages are analyzed followed by a three-phase fault in the power system. A set of comprehensive case studies are performed to verify the proposed control scheme. Keywords Crow bar doubly fed induction generator, oscillation, power oscillation damping controller, reactive power, wind energy conversion systems Introduction The widespread use of renewable energy generation in power industry makes the power system’s control and operations more complicated and intrinsic. The intermittent and unpredictable nature of power output from the renewable sources increases the complexity of power system computations. Because of a non-polluting nature and economic viability, wind energy conversion system (WECS) becomes the most popular renewable energy source. Doubly fed induction generator (DFIG)-based WECS became most popular among wind energy sources because of its high energy transfer capability (Miller, 2010), variable wind speed operation (Akhmatov, 2002) and maximum power extrac- tion from the wind turbine (Shen et al. 2009). The independent active and reactive power control and four quadrant operation makes DFIG-based WECS unique in the renewable energy sector (Datta and Ranganathan, 1999; Xu and Cheng, 1995). A DFIG-based WECS primarily consists of three parts: wind turbine drive train, a doubly fed induction machine and back-to-back converter as shown in Figure 1. Wind drive train consists of turbine which extracts mechanical wind energy, gear box which converts the shaft speed acceptable to the induction machine and the associated control system like pitch and stall controls to regulate the wind power (Pena et al., 1996). The back–to-back voltage source converter (VSC) is capable of bidirectional power flow irrespective of wind speed. The fault ride through (FRT) capability of DFIG makes it possible to stay connected to the grid during the disturbance and maintain synchronism after clearing the fault (Ling, 2016) in the power system. The literatures have proposed the use of static var compensator (SVC) and STATCOM to improve the system inertia (Molinas et al., 2008). But the rating of the SVC and STATCOM need to be improved for an acceptable transient stability margin. To have a reasonable stability margin, the rating should be as good as that of WECS, which increases the overall cost and complexity of the system. 1 Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai, India 2 School of Electrical Engineering and Telecommunications, University of New South Wales Sydney, Sydney, NSW, Australia Corresponding author: K Shanti Swarup, Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai, India. Email: swarup@ee.iitm.ac.in 780385WIE 0 0 10.1177/0309524X18780385Wind EngineeringSimon et al. research-article 2018 Research Article