Research on Method for Obtaining Time Difference of Localization of Transformer PD Source

Abstract:

Ultrasonic positioning accuracy of transformer partial discharge is not high. The main reason is that it is difficult to obtain accurate time difference of the ultrasonic signals reaching two different sensors, especially when the signal-to-noise ratio is not high enough. To solve this problem, Hilbert-Huang transform (HHT) is applied in signal processing to extract the precise moment, and in this way the precise time difference is easily obtained. The signal-to-noise ratio (SNR) of received signal is low, and even worse PD signal is drowned in the strong interference signal. For this, the method named fast independent component analysis (FastICA) is applied in ultrasonic signal denoising before obtaining the time difference. FastICA is not effective in separating the ultrasonic signal from the separated components and in order to solve the problem, envelope identification method is proposed in this paper. In the method, the upper envelope of the signal waveform is sampled and the average of the sampling points is calculated to extract the ultrasonic signal. The numerical result confirmed the practicality of all the mentioned methods.

• Periodical: Applied Mechanics and Materials (Volumes 291-294)
• Pages: 2222-2227
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.291-294.2222
• Online since: February 2013
• Authors: Hong Ling Xie, Bo Yi Shen, Fei Long Wang, Yan Qing Li
• Keywords: Accurate Time Difference, Fastica, HHT, Location, Transformer PD

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