Distributed Temperature Sensing (DTS) uses optical fiber cables as continuous temperature sensors, providing high-resolution, long-distance temperature monitoring for industrial and infrastructure applications.

Overview of DTS Technology

Distributed Temperature Sensing (DTS) systems measure temperature along the entire length of an optical fiber, effectively turning the fiber into a linear sensor . Unlike traditional point-based sensors such as thermocouples or RTDs, DTS provides a continuous temperature profile over distances that can exceed 30 kilometers, with spatial resolutions down to 1 meter and temperature accuracy within ±1°C . This makes DTS particularly suitable for monitoring large-scale assets like pipelines, power cables, tunnels, and industrial plants.

Measurement Principles

DTS relies on optical scattering phenomena within the fiber:

• Raman scattering: High-frequency molecular vibrations in the fiber produce Stokes and anti-Stokes signals, whose intensity ratio depends on local temperature .
• Brillouin scattering: Low-frequency lattice vibrations cause frequency shifts in the light, which can also be used to determine temperature changes . A laser pulse is launched into the fiber, and the backscattered light is analyzed. The time delay of the returning signal allows the system to determine the position along the fiber where the temperature is measured, a method known as Optical Time Domain Reflectometry (OTDR) or, equivalently, Optical Frequency Domain Reflectometry (OFDR) .

Advantages of Optical Fiber Temperature Measurement

• Long-distance monitoring: A single fiber can cover tens of kilometers, reducing the need for multiple discrete sensors .
• High spatial resolution: Continuous temperature profiles allow detection of localized hotspots or anomalies .
• Electromagnetic immunity: Optical fibers are non-conductive and immune to electromagnetic interference, ensuring stable measurements in high-voltage or industrial environments .
• Passive sensing: The fiber does not generate heat, avoiding self-heating errors common in electrical sensors .
• Integration flexibility: Fibers can be embedded in cable sheaths, placed alongside power lines, or installed in confined spaces .

Applications in Western Europe

In Western Europe, DTS technology is widely applied in:

• Power cable monitoring: Real-time temperature monitoring along high-voltage lines to prevent overheating and optimize load management .
• Industrial plants: Continuous temperature mapping in chemical, oil, and gas facilities for safety and preventive maintenance .
• Infrastructure monitoring: Pipelines, tunnels, and critical transport systems benefit from early detection of thermal anomalies .
• Fire detection and leak monitoring: DTS can detect rapid temperature changes, enabling early intervention .

System Components

A typical DTS setup includes:

• Optical fiber cable: Serves as the distributed sensor.
• Interrogator unit: Launches laser pulses and analyzes backscattered light.
• Software interface: Visualizes temperature profiles, calculates metrics like RTTR (Real-Time Thermal Rating), and supports long-term data analysis .
• Optional integration: Control cabinets, servers, and network interfaces for centralized monitoring .

Conclusion

Optical fiber-based DTS systems represent a cost-effective, high-resolution, and reliable solution for temperature measurement across large distances and complex environments. Their adoption in Western Europe spans energy, industrial, and infrastructure sectors, providing continuous monitoring, early anomaly detection, and compliance with safety standards .