The main problem is to determine the bandwidth of the power cable system (PCS) through monitoring of the thermalfluctuation processes cable. Investigated the temperature field in the cross section of the cable in accordance with the theory of heat conduction. The results of studying the thermal conductivity of the PCS. In Matlab, using the system equations Fourier transform in the cylindrical coordinate system is built, the temperature gradient in the cross section of the cable and the environment. On the basis of the thermalfluctuation theory to examine the process of destruction of insulation by thermal vibrations of the atoms, with the partial discharges (PD). The study of failure-free operation of the insulating material PCS. Determined the probability of occurrence of the CR in dependence on influencing factors (temperature, insulation, number and size of inclusions). The distribution of the probability of occurrence of the CR in dependence on a value of density inhomogeneities insulation (y) and the energy of rupture of chemical bonds (D).

Keywords: forecasting, aging of insulation, partial discharges, thermalfluctuation theory