Distributed Temperature Sensing (DTS) is a technology used to measure temperature variations over the length of an optical fiber. It provides continuous temperature profiles along the entire length of the fiber, which can be several kilometers long. DTS is advantageous in applications requiring extensive temperature monitoring over large areas or in hazardous and hard-to-reach environments.
How DTS Works
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Optical Fiber: DTS systems use standard optical fibers as linear sensing elements. The fibers are installed along the area or equipment being monitored.
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Laser Pulse: A laser pulse is sent down the optical fiber. As the light travels through the fiber, it interacts with the glass and scatters in various directions, a phenomenon known as Raman scattering.
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Backscatter Analysis: The scattered light includes components that provide temperature information:
- Anti-Stokes Band: The intensity of this scattered light band is temperature-dependent. Higher temperatures result in higher intensities of anti-Stokes backscatter.
- Stokes Band: Not temperature-sensitive, used as a reference.
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Temperature Calculation: By comparing the intensities of the Stokes and anti-Stokes backscatter, the system calculates the temperature along the fiber.
Benefits of DTS
- Continuous Monitoring: Provides real-time temperature data along the entire fiber length.
- Long-Distance Coverage: Capable of monitoring several kilometers with a single fiber.
- Spatial Resolution: Offers the ability to detect temperature variations with high spatial resolution, often in the range of meters.
- Durability: Optical fibers are rugged and can operate in harsh environments, including extreme temperatures, high pressures, and corrosive conditions.
- Safety: Since DTS uses light instead of electricity, it is safe for use in explosive environments.
Applications of DTS
- Oil and Gas Industry: Monitoring wellbore temperatures, subsea pipelines, and storage tanks for leak detection and process optimization.
- Power Industry: Used in power cable monitoring, detecting overheat conditions in transformers and substations.
- Environmental Monitoring: Used in geotechnical monitoring, such as detecting changes in temperature profiles in permafrost or along glaciers.
- Fire Detection: Early fire detection in tunnels, conveyors, and large infrastructure.
- Process Industries: Monitoring temperature profiles in chemical reactors and processing plants for better control and safety.
DTS technology continues to evolve, with improvements in sensitivity, range, and ease of integration, expanding its applications across different industries.