Wide-frequency Signal Estimation Algorithm Based on Variational Mode Decomposition

With the development of new energy grid connection, power grid broadband oscillation occurs frequently, which is characterized by a wide frequency range, multiple modal components, etc. However, the existing wide-frequency signal estimation methods cannot provide accurate related parameter information due to ignoring the dynamic changes and failing to reduce the mutual interference between components. Therefore, this paper proposes a wide-frequency signal analysis method considering fundamental wave dynamics and reducing mutual interference to achieve high-precision identification of signal parameters and provide data for applications such as wide-frequency oscillation analysis and disturbance location. Firstly, the variational modal decomposition is used to extract the waveform information of various components and the corresponding frequencies. Secondly, considering the dynamic change of fundamental frequency, DFT is used to track the actual frequency. Finally, the frequencies and waveforms are introduced into the dynamic phasor model to realize the parameter estimation. The performance of the algorithm is verified under the situations of linear frequency change, frequency dynamic modulation, noise, etc. The simulation results show that the proposed algorithm can more accurately obtain the parameter information of broad- frequency signal and keep the total vector error less than 3%.