The Measurement and Analysis of Dense Frequency Signals Considering New Energy Integration

In power systems, dense frequency signals (DFSs) comprise several adjacent harmonics or inter-harmonics derived from power electronic devices. Signals that contain two or more significant frequency components within any 15 Hz frequency band are considered DFSs. Existing frequency detection methods cannot detect DFSs with precision in a 10-cycle-period. To solve this issue, an improved dense frequency signal detection (DFSD) method is proposed. Firstly, this paper presents a dense frequency model by which a signal can be decomposed into a series of intrinsic mode functions via complete ensemble empirical mode decomposition (CEEMD). Then, singular value decomposition (SVD) is performed to reduce the dimensions and eliminate noise. Finally, the intensive frequency model is solved via an independent component analysis (ICA), and the parameters of each frequency component are calculated. Simulation and experimental results demonstrate that the proposed method can accurately calculate dense frequency parameters. Considering asynchronous sampling, the proposed method has higher accuracy for harmonic and inter-harmonic detection under the IEC framework.