Measurement of wind farm harmonic emissions

In this paper, harmonic voltage and current measurements performed at the Point of Common Coupling of an existing wind farm comprising five variable speed wind turbines are analyzed and their most important characteristics are presented. Important issues under consideration are the variation of harmonic currents with the wind farm output power, the probability distribution of their magnitude and phase angle, the effect of the application of grouping, according to IEC 61000-4-7, and the selection of averaging time. Further, results from the symmetrical component analysis of the harmonic currents are presented. Finally, an investigation of methods for the separation of wind farm and grid contributions to the harmonic distortion at the Point of Common Coupling is included.