A novel de‐noising method based on coherence average for ultrasonic signal of partial discharge in transformer

Abstract

Ultrasonic method is widely used for the detection and location of partial discharge (PD) in transformer, however, the measured ultrasonic signal is usually corrupted by noise, and sometimes is even buried by noise entirely. Therefore, the de-noising of the measured signal is essential. Conventional de-nosing methods, such as wavelet method and singular value decomposition (SVD) method, generally require empirical parameter selection or estimation, and the best parameters for de-noising vary with the PD source and noise condition, which will bring some limitation to their applicability. More importantly, conventional de-noising methods usually have poor performance for the low signal-to-noise-ratio (SNR) signals. To improve this problem, the paper proposes a de-noising method based on coherence average for the ultrasonic signal. The de-noising performance of the proposed method is evaluated based on a comparison with conventional methods, the results indicate that the proposed method has great de-noising effect for the ultrasonic signals, even for the low-SNR signals. Besides, the proposed method is free from empirical parameter selection or estimation, which can make its applicability more extensive. The proposed method can offer a practical and effective solution to the de-noising of ultrasonic signal of PD in transformer. 1 This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Wavelet Threshold Ultrasound Echo Signal Denoising Algorithm Based on CEEMDAN

“…Several scholars have proposed different calculation methods for analyzing ultrasonic echo signals, including the optimization of transducer models [10], analysis of echo signal spectra [11], and modeling of echo signal parameters [12]. Effective noise reduction is a crucial prerequisite for the accurate analysis of ultrasonic echo signals using various analysis methods [13]. The conventional contemporary method for filtering ultrasonic echo signals involves the use the concepts of Fourier and wavelet transforms.…”