Comparison of interpolation methods in time and frequency domain for the estimation of harmonics and interharmonics according to IEC standard

The fast Fourier transform (FFT) is the most commonly used technique in power systems signals analysis. However, it is known that if the signal is not synchronized or in the presence of interharmonics, the spectral leakage may occur. To overcome this issue, several techniques are found in literature. The present paper will show a comparison between results of calculating the IEC 61000-4-7 harmonics and interharmonics groups and subgroups using two of these techniques, one that uses frequency domain interpolation and other that uses time domain interpolation.