Temperature measurement inside metallic cables using distributed temperature system

Abstract

Nowadays, metallic cables are produced so as to avoid the maximum allowable temperature of the cable by the normal operation and the maximum allowable temperature for short-circuit the exceeding the maximum allowable internal temperature. The temperature increase is an unwanted phenomena causing losses in the cable and its abrasion. Longterm overload can lead to damaging of the cable or to the risk of fire in extreme cases. In our work, we present the temperature distribution measurement inside the metallic cables using distributed temperature system. Within the cooperation with manufacturer of the metallic cables, optical fibers were implemented into these cables. The cables are double coated and the fibers are allocated between these coatings and also in the centre of the cable. Thus we are able to measure the temperature inside the cable and also on the surface temperature along the whole cable length with spatial resolution 1 m during the cable heating. This measurement method can be also used for short-circuit prediction and detection, because this phenomena is always accompanied with temperature increase. Distributed temperature systems are already successfully implemented in temperature measurements in industry environment, such as construction, sewer systems, caliducts etc. The main advantage of these systems is electromagnetic resistance, low application price and the possibility of monitoring several kilometers long distances.