Determination of Current Loads of Cable Lines Laid Underground and Crossing External Heat Sources Using Mathematical Simulation of Steady-State Heat Conduction Processes

In urban areas, the capacity of power cable lines is significantly influenced by adjacent cable lines, cable blocks, heat pipelines, and other external sources of thermal impact, which may be laid either parallel to or at an angle to the cable line. The most effective and versatile method for determining nominal current loads in this case is mathematical simulation using modern software packages. This article presents a study of the steady-state thermal conductivity of a power cable line laid in a soil mass with an external source of thermal impact, positioned either perpendicular or parallel to the cable line. The problem was solved in a three-dimensional formulation. The cable line, laid in a horizontal plane within a homogeneous soil mass at a depth of 1.2 m, consists of three single-core cables rated for 10 kV with cross-linked polyethylene insulation. The external heat source is a homogeneous cylindrical body. In constructing the geometric model, the layers around the conductive core were replaced with an equivalent layer, for which the thermal conductivity coefficient was determined taking into account the geometry, thermal conductivity coefficients of the main construction elements, and thermal losses in the screen. The problem was solved using the Ansys software package. The impact of the external thermal source on the reduction of nominal current load and the increase in cable temperature at a specified current was investigated.