A System Transient Stability Enhancement Control Method Using Doubly Fed Induction Generator Wind Turbine with Considering Its Power Constraints

Di Zheng,Xiaofu Xiong,Jinxin Ouyang,Mengyang Li,Chao Xiao

doi:10.3390/en11040945

Di Zheng, Xiaofu Xiong + Show 3 more

Open Access

https://doi.org/10.3390/en11040945

Copy DOI

Journal: Energies	Publication Date: Apr 16, 2018
Citations: 10	License type: CC BY 4.0

Affiliation: Chongqing University

Abstract

With the rapid development of wind power, the effects of doubly fed induction generators (DFIGs) on the transient stability of power system have attracted more attention. However, the effects are still not clear due to the lack of deep and theoretical analysis. A control method for enhancing system rotor angle stability enhancement is proposed with considering the power constraints of DFIG. The rotor angle oscillation of the synchronous generator (SG) can be reduced and overspeed and the overcurrent of DFIG can be avoided. In this paper, the effects of the DFIG on the rotor angle characteristics of SG are analyzed. The change law of system rotor angle varying with transient power of the DFIG is obtained. Then, the power equation in the emergency pitch control process is explored. The reactive power constraints of the stator and grid-side converter are deduced. Finally, the system rotor angle stability enhancement control method is proposed based on the power constraints of DFIG. The effectiveness of proposed method is proven by simulations.

Highlights

Fed induction generators (DFIGs) have become the mainstream of wind turbines in the past several decades [1]
This study aims to obtain the effect of Doubly fed induction generators (DFIGs) on system rotor angle characteristics and propose a rotor angle stability enhancement control method using the DFIG
If the DFIG disconnects from the grid because of overspeed at point e, the reactive power support that is provided by the DFIG disappears

Summary

Introduction

Fed induction generators (DFIGs) have become the mainstream of wind turbines in the past several decades [1]. A decoupled-DFIG strategy was presented in [7] that the active power of stator and reactive power of the grid-side converter (GSC) could be improved to enhance the stability performance under the induction generator mode. Though the reactive power capacity considering the constraint of rotor speed was discussed in [13], the relationship between the rotor speed and active power may be not accurate under the grid fault. It was advocated in [11] that the reactive power of DFIG was restricted by converter current as well as rotor speed.

Transient Power of DFIG

Effect on Rotor Angle Characteristics

Active Power Constraint

Reactive Power Constraint

Transient Power Constraints in GSC

Case Studies

Conclusions