Verification of the reactive power requirements in wind farms

Reactive power must be measured and watched to verify accomplishment of Spanish grid code requirements in wind farms. However, no definition of reactive power is established in that code. Thus, two reactive power formulations are compared in this paper applied to wind farm generators in presence of transient disturbances such as voltage dips. First reactive power formulation is based on Emanuel´s approach, included in the IEEE Standard 1459-2000. Second reactive power formulation has recently been established by Czarnecki. Both formulations express reactive power decomposed into the reactive power due to the reactances and the reactive power caused by the unbalances. This decomposition allows for a better knowledge of wind farms working and to verify the accomplishment of code grids established in several countries.