Temperature Monitoring of buried power cables

Temperature Monitoring of buried power cables

It involves temperature measurement of a buried power cable by fibre optic technology, which allows the transmission capacity to be optimised.

The aim of the project is the development of a demonstration of fibre optic distributed temperature sensing (FO-DTS) technologyto monitor the temperature of insulated cable and empirically analyse the ability to withstand overloads and the influence of cyclic loadingon the transmission capacity of insulated power cables. The ultimate goal is to achieve a more flexible operation and planning of the grid, without ever exceeding the maximum operating temperature.

Power cable

Course of action:

Currently, transmission grid cables are operatedunder a single capacity which only takes into account the ampere load of the installation, regardless of the temperature value it reaches, although in reality, the capacity of an insulated cable installation depends on the temperature it reaches. The use of a capacity that is fixed and non-dependent on the actual temperature of the installation, signifies that the full potential of the installation cannot be used in real time and means that facilities that are considered overloaded, may not actually be so.

The technology which is the object of this development, provides temperature monitoring of the cable based on the use of built in fibre-optic (FO) in the sheath of insulated cables. This innovative arrangement reduces theoretical calculations and interpolations by directly measuring the temperature very close to the conductor. Additionally, the intention is to install additional FO outside of the cables to compare the results and reliability depending on the location of the measurement point of providing redundancy and safety to measurement.


The project was completed in 2016.


Red Eléctrica has developed this project without the collaboration of other companies.

Benefits to the electricity system:

Analysingthe theoretical studies that have been conducted on the subject, it is considered that knowing the temperature of the installation can help take advantage of the full potential of buried cable installation, greatly increasing the transmission capacity currently considered, providing information about the actualoverload capacity should a system failure occur, optimising sections / distances and providing data for possible predictive maintenance and preservation of the useful life of our facilities, as well as the identification of the influence of other converging infrastructures.