Comparison of Transient Stability between Wind Farm Based on DFIG and Traditional Power Plant in an Actual Grid

As a clean renewable energy, wind energy draws more and more attention around the world. In case of high wind speed or low speed but substantial installed wind power capacity, wind turbine generators (WTGs) will take the place of traditional power plant partly. Under the circumstance, the transient stability will change. Therefore, in this article, the synthetical dynamic model of WTG is introduced first, and on the basis of it, the article focus on the comparison of transient stability characteristic between wind farm based on double fed induction generator (DFIG) and tradition power plant with the same capacity. Take an actual grid including wind farm as an example. The power factor of the wind farm is 1.00 and keeps constant during steady state. Under this control mode, the reactive power between wind farm and the grid is zero. The study indicates that, in this system, when the scale of wind farm connected is below 12.3%, the transient stability is better than synchronous generator integrated with the identical capacity. And with the increasing capacity of wind farm, the fault critical clearing time (CCT) is shorter, and it lasts longer time during the recovery. When the scale of wind farm exceeds 12.3%, the terminal voltage of point of common coupling (PCC) is below 0.95 p.u. The stability is inferior to the synchronous generator connected. Under the circumstance, the stability will be enhanced through adding the reactive power compensative device.