Thermal aging management of underground power cables in electricity distribution networks: a FEM-based Arrhenius analysis of the hot spot effect

The effects of solar irradiation, wind and moisture on the thermal aging of underground power cables in electricity distribution networks cannot be included in the traditional Arrhenius model by means of any temperature rise or any derating factor. Such effects can be taken into account only if the Arrhenius model is coupled with a finite element method (FEM)-based steady-state thermal model and the Miner’s cumulative damage law. Accordingly, this study aims to analyze the effect of an actual hot spot on the thermal lifespan of a 110 kV underground cable line using a FEM-based Arrhenius model and considering solar irradiation, wind velocity, and soil moisture content. The 110 kV underground line consists of cables with cross-linked polyethylene (XLPE) insulation. The considered parameters are logically changed within the frames of the most unfavorable summer conditions and the most common winter conditions. The FEM-based Arrhenius model used was developed for the purpose of thermal aging management of power cables by Klimenta JLj, Panić MV, Stojanović MS et al. in early 2022. The existing calculated and experimental data on XLPE insulation are used for the purposes of verification and validation of the model, respectively. Finally, the hot spot effect is quantified and analyzed for all the considered parameters.