The impact of harmonics calculation methods on power quality assessment in wind farms

Different methods of calculating harmonics in measurements obtained from offshore wind farms are shown in this paper. Appropriate data processing methods are suggested for harmonics with different origin and nature. Enhancements of discrete Fourier transform application in order to reduce measurement data processing errors are proposed and compared with classical methods. Comparison of signal processing methods for harmonic studies is presented and application dependent on harmonics origin and nature recommended. Certain aspects related to magnitude and phase calculation in stationary measurement data are analysed and described. Qualitative indices of measurement data harmonic analysis in order to assess the calculation accuracy are suggested and used.