Effects of electrical and mechanical parameters on the transient voltage stability of a fixed speed wind turbine

In this paper the dynamic behaviour of a wind turbine connected to the grid is examined. The model of the fixed speed wind turbine has been developed with the Simulink simulation tool (Matlab Inc.) It is composed of the induction generator, the shaft system, an aerodynamic model of the wind turbine rotor and the pitch control system. Using this model, a three-phase fault is applied close to the wind turbine and cleared by disconnecting the faulty line.The rigorous implementation of the simulink model allowed the authors to evaluate the exact dependence of various electrical parameters for the induction generator on voltage stability. Furthermore, the effects of wind turbine mechanical construction and of grid parameters on voltage stability are also evaluated and discussed.For each parameter, the terminal voltage and the generator rotor speed for different fault-clearing times are drawn. Finally, the terminal voltage and the generator rotor speed obtained for a fifth order model of the induction generator are compared with those obtained for a third order model. The differences between the two models are discussed. The results will help to understand transient stability phenomena in wind farms.

Research highlights
► We model the dynamic behaviour of a wind turbine connected to a stiff grid using Simulink simulation tool (Matlab Inc.).
► We examine the voltage stability of the wind turbine system assuming a three-phase fault close to the wind turbine.
► For each electrical/mechanical parameter, the terminal voltage and the generator rotor speed for different fault-clearing times are drawn and the dependence of each of them on the voltage stability is evaluated.