How to Monitor Pipeline Vibration with Distributed Fiber Optic Sensing Technology-INNO

سنسور دمای فیبر نوری, سیستم مانیتورینگ هوشمند, تولید کننده فیبر نوری توزیع شده در چین

دستگاه اندازه گیری دمای فیبر نوری فلورسنت

سیستم اندازه گیری دمای فیبر نوری فلورسانس توزیع شده

The fully distributed fiber optic sensing technology can be applied in different fields, and the product categories mainly include distributed fiber optic temperature measurement, distributed fiber optic vibration monitoring, distributed strain stress monitoring system, غیره.

Distributed fiber optic sensing technology has advantages such as continuous distributed detection, long detection distance, موقعیت یابی دقیق, rich measurement information, intrinsic safety, and low cost. It has been widely used in fields such as power, روغن, bridges, tunnels, and slopes.

Among various fiber optic sensing technologies, the distributed fiber optic sensing device based on Brillouin scattering effect is a new type of sensing device that directly uses fiber optic as the sensing element, combining “transmission” and “sensing”, and can sense the temperature and/or strain along the fiber optic line. The distributed fiber optic sensing device includes a light source, a fiber ring resonator, an optical fiber, and a detector. The laser emitted by the light source is coupled into the optical fiber through the fiber ring resonator, and various scattering effects are generated during the transmission of the laser in the optical fiber. در میان آنها, the frequency shift of backward Brillouin scattering is related to the temperature and/or strain along the optical fiber, and backward scattering in the optical fiber.

The necessity of pipeline monitoring system

It is a structural monitoring system that uses modern sensing technology and communication network technology to optimize the combination of monitoring objects such as pipeline networks, adjacent geological structures, and environmental variables. It can monitor the structural response and geological changes of underground pipeline networks in real time under various environmental factors, and effectively provide scientific basis for pipeline network management, significantly improving the overall management level of pipeline networks, thereby ensuring safe operation, predicting hazards, and extending service life to the maximum extent possible.

The implementation of some major projects, such as the South to North Water Diversion, West to East Gas Pipeline, the construction of the four major energy channels between China and Russia, Central Asia, China and Myanmar, and the sea, has laid tens of thousands of kilometers of oil, gas, and water pipelines nationwide. These pipelines require continuous operation, and once pipeline failures occur, they will bring huge economic losses, environmental damage, and potential dangers. Most pipelines are buried deep underground or underwater, resulting in low real-time and efficiency of pipeline monitoring. Pipeline safety accidents generally manifest in three forms: pipeline damage caused by natural environment and geological disasters; Artificial construction and destruction; The pipeline has been in service for a long time, and the damage and leakage caused by corrosion of the pipeline. The current safety issues and concerns of oil, gas, and water pipelines are: oil pipelines may break due to external forces; Accidents caused by gas leaks or geological disasters in gas pipelines; Water supply pipelines are intentionally damaged during municipal construction in urban areas.

What are the traditional pipeline monitoring methods

Pipeline safety monitoring often adopts methods such as manual inspection, acoustic detection, and software analysis, which all have some problems and disadvantages:

(1) Manual inspection has low cost, but it cannot be monitored in real time, has low efficiency, and is prone to human negligence causing omissions, posing safety hazards;

(2) Acoustic detection has a high cost and can monitor all situations in real time, but it requires the installation of many acoustic sensors along the pipeline and is difficult to maintain;

(3) Software analysis can detect leaks and locate them, but cannot detect damages, resulting in high costs, limited domestic applications, and inconvenient maintenance.

Distributed Fiber Optic Pipeline Monitoring and Sensing Technology

این distributed fiber optic vibration monitoring system (distributed fiber optic acoustic sensing DAS system) mainly consists of a vibration measurement host, a vibration sensing optical cable, and monitoring software. Based on Ø – OTDR, phase interference, and phase demodulation technology, it detects the interference Rayleigh echo scattered light, identifies the phase, polarization state, and other information of the optical cable vibration position after photoelectric conversion, and uses phase demodulation algorithm to achieve accurate real-time monitoring of distributed disturbances.

The detection range of this system can reach up to 50 kilometers, achieving a positioning accuracy of 2 meters within a range of 5 kilometers and 20 meters within a range of 50 kilometers. For weak signals, phase demodulation can accurately identify the frequency and time-domain waveform of external vibration sources in real time, accurately analyze the time-frequency characteristics of vibration sources, and draw a three-dimensional spectrum of distance vibration frequency vibration intensity. It can be used for real-time monitoring of intrusion prevention, gas pipeline leakage positioning and other projects.