Determination of Insulation Heating with Registration of the Cable Lines Joint Wiring

The article deals with heating of the cable lines insulation, which is one of the main factors determining its condition. To study the thermal process, which has a random character, we have analyzed the statistical data of various heating factors: the load current, the reverse sequence current of the fundamental frequency, the currents of the higher harmonic components, as well as the interharmonic components. It is shown that the heating temperature largely depends not only on the current flowing through the cable, but also on the presence of higher current harmonics, and also on the number of cables laid side by side in the same trench. It is proposed the method taking into account during temperature calculation the thermal influence of the cables laid side by side. The result shows that the heating temperature of the cable increases with simultaneous laying and the proposed method makes it possible to estimate such increase in temperature in order to avoid heating the cables above the permissible value, especially taking into account the possibility of the higher current harmonics flow through the cable.