Fem-Based Thermal Analysis of Underground Power Cables Located in Backfills Made of Different Materials

Abstract

This paper presents the preliminary thermal analysis of the underground transmission line, which will be applied in the Polish power plant that produces 600 MW of power. The paper considers a system of three power cables located in the in-line arrangement placed in the HDPE casing pipes buried in the multilayered soil (the native soil and the thermal backfill). Different configurations of bedding layers are analyzed. The burial depth of the cables, measured from the reference level (0.5 m below the ground) varies from 2 to 6 m. What influences the temperature distribution in soil, cable bedding and cable conductor. The numerical computations of the steady-state temperature fields are performed using the finite element method. Additionally, to include the dry-zone formation effect on the temperature distribution, the soil thermal conductivity is considered to be temperature-dependent.