An ESPRIT and DFT-based new method for the waveform distortion assessment in power systems

Discrete Fourier transform (DFT) is recommended for waveform distortion assessment in IEC standard framework. One of the most important problems for DFT application is the spectral leakage. It was shown in the literature that the most remarkable errors due to leakage problems in power system waveform assessment are mainly due to the errors in synchronizing fundamental and harmonics. In this paper, a new two-steps signal processing technique based on ESPRIT and DFT methods is proposed. This technique guarantees a fast and accurate synchronization of fundamental and harmonics; it also allows to obtain an accurate evaluation of the low frequency interharmonics. The proposed method is applied on test waveforms in order to demonstrate its effectiveness in terms of reduced computational efforts and accuracy of the results.