Bi-Signature optical spectroscopy for online fault detection in electrical machines

• Main Authors: Belema P. Alalibo, Wenping Cao, Zheng Liu
• Format: Article
• Language: English
• Published: Wiley 2019-05-01
• Series: The Journal of Engineering
• Subjects: condition monitoring; Bragg gratings; fibre optic sensors; spectral analysis; fault diagnosis; electromagnetic interference; temperature measurement; vibration measurement; zero electromagnetic interference; non-intrusive real-time condition monitoring; vibration sensitivity; temperature sensitivity; bi-signature optical spectroscopy; industrial machines; long period grating; online fault detection; fibre-optic sensors; Bragg wavelength shifts; electrical machine; optimal detection signature; fibre Bragg gratings
• Online Access: https://digital-library.theiet.org/content/journals/10.1049/joe.2018.8062

A novel bi-signature optical spectroscopy for fault detection in electrical machines is presented. The combined use of long period grating (LPG) and two fibre Bragg gratings (FBG1 and FBG2) is implemented to discriminate between vibration and temperature sensitivity in the detection of machine faults. With LPG having higher sensitivity to temperature compared to both FBGs, machine faults are detected through spectral analysis of both signatures; and the optimal detection signature for each fault is consequently analysed. This novel technique utilises the principle of a shift in the wavelengths of the gratings to determine the kind of fault present in an electrical machine as the signature spectroscopy reveals varying amount of Bragg wavelength shifts for various fault types. The use of FBG sensing for fault detection in electrical machines has the potential of revolutionising non-intrusive real-time condition monitoring of future industrial machines with high reliability due to zero electromagnetic interference (EMI) as well as significant low cost of fibre-optic sensors.