Power harmonic and inter-harmonic detection based on fractional wavelet transform combined with variational modal decomposition algorithm.

Aiming at the problem of present power harmonic and inter-harmonic detection methods, which are susceptible to noise interference and have low detection accuracy for inter-harmonics, a novel power harmonic and inter-harmonic detection method based on fractional wavelet transform (FRWT) combined with variational mode decomposition (VMD) is proposed. The FRWT-VMD algorithm first preprocesses the signal with FRWT and VMD. Second, the VMD is used to extract harmonics and inter-harmonics. The method incorporates the advantages of the FRWT and VMD methods, corrects the defect that the FRWT method is difficult to detect inter-harmonics, and improves the problem that the VMD method is susceptible to noise interference. Simulation tests on various power harmonic signals have shown that under low signal-to-noise ratio conditions, the FRWT-VMD algorithm can effectively reduce the impact of noise and has high accuracy in harmonic and inter-harmonic detection. It is a powerful method for detecting harmonics and inter-harmonics in power systems.