A Measurement Method of Supraharmonics Based on Partial Sampling and Hybrid Segmentation

The widespread use of high-frequency power electronics has caused the problem of supraharmonics in the power grid to become increasingly serious. However, the existing harmonic measurement method has problems such as slow measurement speed and a large amount of processing data when measuring supraharmonics with a wider frequency range. Furthermore, there is no uniform and effective standard for the supraharmonics measurement. In this paper, based on a comprehensive analysis of the correlation between the frequency characteristics of supraharmonics generated by power electronic converter equipment and the switching frequency, a hybrid measurement method based on characteristic frequency segmentation is proposed. The harmonic peak is obtained by partial sampling FFT operation to calculate the switching frequency, the segmentation strategy of the spectrum aggregation is automatically determined according to the peak characteristics around the switching frequency and its multiple frequencies. The simulation analysis shows that the proposed method can effectively improve the measurement speed based on the accurate measurement of supraharmonics. The field-test results verify the feasibility and effectiveness of the method. This paper provides a new idea to unify the supraharmonics measurement standard.