Fiber optic sensors can be classified as single-point, multipoint or quasi-distributed, and distributed sensors. Temperature measurement using DTS and optical fiber belongs to the distributed category.

The article describes industrial systems measuring temperatures at one-meter intervals, with channel ranges of 6, 10, 15, 30 or 50 km. Depending on the measurement environment, temperature accuracy can reach 0.03 degrees Celsius.

Advantages of distributed fiber optic temperature sensing include high sensitivity; resistance to vibration; inertness and resistance to corrosion and chemicals; versatility; resistance to environmental interference such as electromagnetic fields, microwaves, high frequencies, radio signals, lightning and humidity; suitability for high temperatures; durability and reliability in demanding environments, with a service life exceeding 30 years; no electrical power supply at the sensor; no electronic devices or moving parts in the monitored area; suitability for explosive and flammable environments; minimal space requirements in ducts, wells and pipes; long-distance remote monitoring; compatibility with data transmission networks; and cost effectiveness.

Applications include power cable and extra-high-voltage cable temperature monitoring; conveyor temperature and fire monitoring; busduct, busbar and busway protection; pipeline temperature and leak monitoring; utility tunnel fire detection; high-temperature and cryogenic equipment monitoring; LNG tank and pipeline leak detection; floating-roof oil tank fire detection; steam and district heating pipeline leak monitoring; and reactor temperature monitoring.