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Nowadays, the power cables are manufactured to fulfill the following condition – the highest allowable temperature of
the cable during normal operation and the maximum allowable temperature at short circuit conditions cannot exceed the
condition of the maximum allowable internal temperature. The distribution of the electric current through the conductor
leads to the increase of the amplitude of electrons in the crystal lattice of the cables material. The consequence of this
phenomenon is the increase of friction and the increase of collisions between particles inside the material, which causes
the temperature increase of the carrying elements. The temperature increase is unwanted phenomena, because it is
causing losses. In extreme cases, the long-term overload leads to the cable damaging or fire. This paper deals with the
temperature distribution measurement inside the power cables using distributed temperature system. With cooperation
with Kabex company, the tube containing optical fibers was installed into the center of power cables. These fibers,
except telecommunications purposes, can be also used as sensors in measurements carrying out with distributed
temperature system. These systems use the optical fiber as a sensor and allow the continual measurement of the
temperature along the whole cable in real time with spatial resolution 1 m. DTS systems are successfully deployed in
temperature measurement applications in industry areas yet. These areas include construction, drainage, hot water etc.
Their advantages are low cost, resistance to electromagnetic radiation and the possibility of real time monitoring at the
distance of 8 km. The location of the optical fiber in the center of the power cable allows the measurement of internal
distribution of the temperature during overloading the cable. This measurement method can be also used for prediction
of short-circuit and its exact location.
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