Field Application of Switchgear Abnormal Noise Detection Based on Acoustic Imaging Technology

In order to realize the non-contact acoustic imaging location and identification of switchgear abnormal noise type, this paper mainly combines three cases of abnormal noise defect caused by mechanical looseness or internal discharge of on-site switchgear, and uses the acoustic imaging method to locate the noise source. At the same time, the time-domain, time-frequency and frequency spectrum characteristics of mechanical looseness and discharge are analyzed. It is obtained that after filtering out the frequency of 10 kHz and below, the waveform shows obvious pulse form in the case of discharge abnormal noise, while the waveform is irregular noise in the case of mechanical looseness. Whether it is mechanical looseness or internal discharge, its energy is mainly concentrated below 2 kHz.For abnormal noise of mechanical looseness, 0–2 kHz energy ratio accounts for more than 99%, 10–20 kHz energy ratio accounts for less than 0.5%, while for abnormal noise of internal continuous stable discharge, 10–20 kHz energy ratio accounts for more than 2%. In this paper, a feasible method is provided for the preliminary identification of abnormal noise defect type through time domain waveform, time-frequency diagram, energy ratio and frequency spectrum diagram.