Research Of Equivalence Method About Wind Farm Static And Dynamic Models

The operation characteristics of wind turbine generators and wind farm determine its impacts on the power system. Wind turbine generator and wind farm models, which could accurately reflect its operation characteristics,are the basis for other studies. Usually, a large-scale wind farm cotains hundreds of wind turbine generators. Thus, detailed modelling of wind farm is not necessary and inefficient. Under the premise of ensuring the accuracy and efficiency, it is necessary to study for engineering requirements of the wind farm equivalent method.In simulation research, a large scale wind farm is practically equivalent to be one aggregated model. The existing equivalence methods only consider the external characteristics of wind farm, and ignored the coupling relationship between units and power system.First, this paper proposes a static equivalence method according to the same loss of the wind farm internal electrical connection. Secondly, based on the 3-order dynamic equation of DFIG, the closed loop transfer function about DFIG is derived and the corresponding root locus about DFIG is got. And also, the relationship between system gain and DFIG operating point is established. From the theoretical perspective, this paper make a qualitative description about the power system damping will change if the wnid farm operation is changed. Meanwhile, through a massive simulation under different wind power mode scheduling and unit's operating point, this paper shows a wind farm operation mode, which its impacts on power system is severe, and a wind farm caculation model based on full operation mode is proposed. Finally the effect of the equivalence method is validated by comparing the aggregated and detailed models.