Harmonic Frequency Identification Method Based on Recording Data and Impedance Model

With the large-scale incorporation of power electronic equipment to new-type power systems, the content of high-frequency harmonics exhibits an increasing trend. The bandwidth and sampling frequency of the existing harmonic measurement devices are mainly designed for low-frequency harmonic measurement requirements, which may lead to high-frequency harmonic measurement distortion. In response to this issue, this paper proposes a harmonic frequency identification method based on recording data and impedance model. This method applies voltage and current recording data and network parameters to calculate the system impedance, respectively. The deviation between the calculated results is adopted to determine the harmonic frequency of measurement distortion. Additionally, the possible real harmonic frequency is calculated based on the principle of spectrum aliasing, and the system impedance at this frequency is recalculated to identify the real harmonic frequency. In the end, simulation and field cases analysis are used to validate the effectiveness of the suggested approach. The findings demonstrate that the suggested approach is capable of precisely identifying the real high-frequency harmonics in the case of spectrum aliasing.