Distributed Optical Fibre Sensors and their Applications in Pipeline Monitoring

Abstract

Health monitoring of civil infrastructure systems has recently emerged as a powerful tool for condition assessment of infrastructure performance. With the widespread use of modern telecommunication technologies, structures could be monitored periodically from a central station located several kilometres away from the field. This remote capability allows immediate damage detection, so that necessary actions are taken to reduce the risk. Optical fiber sensors offer a relatively new technology for monitoring the performance of spatially distributed structures such as pipelines. In this regards, several commercially available strain and temperature sensing equipment such as discrete FBGs (Fibre Bragg Gratings) and fully distributed sensing techniques such as Raman DTS (distributed temperature sensor) and Brillouin Optical Time Domain Reflectometry (BOTDR) typically offer sensing lengths of the order of 100 km's. Distributed fiber optic sensing offers the ability to measure temperatures and/or strains at thousands of points along a single fiber. In this paper, the authors will give a brief overview of these optical fiber technologies, outline potential applications of these technologies for geotechnical engineering applications and experience in utilising BOTDR in water pipeline monitoring application.

Characterization of the corrosion of iron using a smartphone camera

“…When the green and blue responses are compared to the red, the relationships are very similar to their response to increasing corrosion as shown by 1.13 21 GR [6] 1.18 29 BR [7] However, when the green and blue channel responses are normalized to red responses (G' and B' respectively) and compared to the proportion of corrosion, the relationship is a broad negative parabola (Figure 4). The coefficients of the parabola are less than 10 -4 .…”

“…Qi and Gelling [5] summarized the main sensors used to detect corrosion as being one or a combination of electromagnetic, electrochemical, optical fluorescent, and optical fiber mechanisms, all based on the chemical, galvanic, and optical properties. In pipes, fiber optic systems have proven to be invaluable in detecting corrosion [7][8] . For concrete reinforcement, the use of impedance capacitive sensors has been found to be effective in alerting people to corrosion that is not visible [9] .…”

Novel Negative Pressure Wave-Based Pipeline Leak Detection System Using Fiber Bragg Grating-Based Pressure Sensors

“…At present, there are many methods and techniques reported for PLD [5], [6], the most important being leaking medium detection [7], [8], pipe wall parameter detection [9], the use of acoustic principles [10], [11], and optical fiber sensing detection [12], [13]. These methods differ in cost, effectiveness and applicability to different situations as well as how they may be deployed for long lengths of pipe, and in different weather or climatic conditions, for example.…”

“…Optical fiber-based methods offer a very satisfactory solution to measurement needs of this type: the sensors are physically robust and have the advantages of small size, light weight, resistance to corrosion and low signal loss [14]- [16]. The techniques reported in recent years for fully distributed fiber optic monitoring have mainly focused on the use of fiber optic sensor systems based on Brillouin scattering, Raman scattering or interferometry and these have been tested on some pipelines [12], [13]. However, such techniques have shown some limitations for practical use.…”

Fiber optic distributed temperature sensor mapping of a jet-mixing flow field

“…Both can be many kilometers long and have found use in measuring temperature within oil wells (Williams et al 2000) and along power cables serving offshore wind farms (Fromme et al 2011), as well as strain within infrastructure such as tunnels and pipelines (Rajeev et al 2013). Brillouin systems can achieve spatial resolution down to ~1 cm, while Raman is limited to ~1 m; time response is generally on the order of minutes (Bao and Chen 2012) though some commercial systems can now achieve data rates of approximately 1 Hz.…”