Clear imaging method based on far-field beamforming for substation noise source identification

Abstract

The noise problem of substations has become increasingly prominent in recent years, and the accurate identification of noise sources has been the prerequisite for substation noise control. By virtue of the advantages of long measurement distance and panoramic acoustic imaging, far-field beamforming based on solid spherical microphone arrays has broad application prospects in large substation noise source identification. Spherical harmonics beamforming (SHB) is a classical algorithm matched with spherical microphone arrays. However, its sound source identification results suffer from problems such as wide mainlobes at low frequencies and abundant sidelobes at high frequencies, which lead to limited acoustic imaging clarity. In order to achieve clear acoustic imaging of noise sources in large substations, the output of far-field SHB is reconstructed and the method of clear SHB (C-SHB) is proposed. The simulations and experiment show that C-SHB can significantly reduce the mainlobe width and suppress the sidelobe contamination, thus effectively improving the imaging clarity of SHB and enhancing its weak source identification capability.