Generation capability curves for wind farms

A capability curve reflects the maximum active and reactive power that a synchronous generator can deliver at its terminals. For a typical power station, the maximum generating power is given by the aggregate of the individual capability curve for each generator. In the case of a wind farm, however, the maximum generating power cannot be obtained by the aggregation of the capability curve for each wind turbine due to the presence of impedances in the collector system, the substation and transmission lines. It is convenient to determine the overall generating capability of a wind farm by incorporating these impedances to determine the maximum active and reactive power at the point of common coupling. This paper describes the steps required to determine the capability curve of a wind farm and enumerates the factors affecting the shape of this curve.