Wyniki wyszukiwania - BazTech

1

“Current – polarization-dependent loss” optical fibre sensor

Torbus Sławomir Andrzej

Przegląd Elektrotechniczny

|

2019

|

R. 95, nr 5

171--174

EN

The study briefly discusses the Faraday magneto-optic effect, design and working principle of the polarimetric current sensor and the polarization-dependent loss. The study presents a concept of a “current – polarization-dependent loss” optical fibre sensor for current measurement in power lines. A method for measuring polarization loss using optical reflectometer is presented. Test results on the effect of GeO2 dopant in a single-mode optical fibre core, wavelength and optical fibre length on the polarization loss are presented. The conclusions on selecting the optical fibre and wavelength in the design of a “current – polarization-dependent loss” optical fibre sensor are formulated.

PL

W pracy krótko scharakteryzowano magnetooptyczne zjawisko Faradaya, budowę i zasadę działania polarymetrycznego czujnika natężenia prądu oraz tłumienie zależne od polaryzacji. Zaprezentowano koncepcję światłowodowego przetwornika „prąd – tłumienie zależne od polaryzacji”, który może być wykorzystany do pomiaru natężenia prądu w liniach elektroenergetycznych. Omówiono metodę pomiaru tłumienia polaryzacyjnego przy użyciu reflektometru optycznego. Przedstawiono wyniki badań dotyczących wpływu stężenia molowego domieszki GeO2 w rdzeniu światłowodu jednomodowego, długości fali świetlnej oraz długości włókna światłowodowego na wartość tłumienia polaryzacyjnego. Sformułowano wnioski dotyczące doboru włókna światłowodowego i długości fali świetlnej do realizacji światłowodowego przetwornika „prąd – tłumienie zależne od polaryzacji”.

2

A high performance distributed sensor system with multi-intrusions simultaneous detection capability based on phase sensitive OTDR

Zhan Y., Yu Q., Wang K., Yang F., Kong Y., Zhao X.

Opto-Electronics Review

|

2015

|

Vol. 23, No. 3

187-194

EN

A high performance distributed sensor system with multi-intrusions simultaneous detection capability based on phase sensitive OTDR (Φ-OTDR) has been proposed and demonstrated. To improve system performance, three aspects have been investigated. Firstly, a model of one-dimensional impulse response of backscattered light and a Monte Carlo method have been used to study how the laser line width affects the system performance. Theoretical and experimental results show that the performances of the system, especially the signal-noise-ratio (SNR), decrease with the broadening of laser linewidth. Secondly, a temperature-compensated fibre Bragg grating with a 3 dB linewidth of 0.05 nm and a wavelength stability of 0.1 pm has been applied as an optical filter for effective denoising. Thirdly, a novel interrogation method for multi-intrusions simultaneous detection is proposed and applied in data denoising and processing. Consequently, benefiting from the three-in-one improvement, a high performance Φ-OTDR has been realized and four simultaneous applied intrusions have been detected and located at the same time along a 14 km sensing fibre with a spatial resolution of 6m and a high SNR of 16 dB. To the best of our knowledge, this is the most multifunctional Φ-OTDR up to now and it can be used for perimeter and/or pipeline intrusion real-time monitoring.

3

Monitoring system of extreme loadings of propulsion system’s foundation : design assumptions

Kyzioł L., Murawski L.

Journal of KONES

|

2013

|

Vol. 20, No. 1

155--162

EN

Project of on-line diagnostic (monitoring) system of marine propulsion system working parameters is the authors' general target. Proper propulsion system’s foundation is one of the most important parameters for its reliable operation. Different types of quasi-static loadings and dynamic excitations can be observed during ships exploitation. Presented research has been limited to extreme loadings. Underwater explosions or ship groundings are considered examples of extreme foundation loadings. Analysis of the physical parameters of the extreme forces has been presented in the first part of the paper. Water pressure spatial and non-spatial (time) distribution during underwater explosion has been analysed as an example. Short overview of the dynamic mathematical models of underwater explosions is presented. Time function of vibrations acceleration of ship construction is important design assumption of planned Structural Health Monitoring (SHM) system. Propulsion system's foundation loading measurements should take into account general ship hull deformation (in the aft part of the ship) as well as reactions changes of main engine and shaft line bearings. Ship hull deformation should be monitored as quasi-continuous measurements, along whole propulsion system. Optical Time-Domain Reflectometer method (OTDR) is planned for hull deformation monitoring. Propulsion system bearings' reactions are a source of local foundation pads' strain changes. Fibre Bragg Grating (FBG) sensors are the best for that kind of measurements, in authors opinion. Both techniques (OTDR and FBG) have been shortly described in the paper. Scheme of monitoring system of marine propulsion systems foundation's loadings are proposed in the end of the article.