Non-Concentric Ladder Soil Model for Dynamic Rating of Buried Power Cables

This paper presents a new, non-concentric ladder soil model for dynamic rating of buried power cables. For both, deep and shallow burial, static isotherms within the soil form non-concentric cylinders around a single cable. These isotherms are used to design a non-concentric ladder soil model. For multiple cables, isotherms may have a complex shape, and heat capacities of the soil layers are calculated numerically. The new model gives precise dynamic rating results in excellent agreement with physical simulations based on the finite element method (FEM). It also allows to calculate temperature profiles within the soil surrounding the cable.