Determination of the Rated Current Loads of Cable Lines with Distributive Parameters

Abstract

The power transfer capacity of cable lines is substantially affected by the conditions of cable laying. The laying of power cables at a rated ac voltage of 10 kV and frequency of 50 Hz with an aluminum multiwire compacted current-carrying conductor with a cross section of 240 mm2 and XLPE insulation in a cable channel, which is placed into the ground and filled with air, has been considered. The suggested technique to determine rated current loads of cables in the cable channel with the distributive parameters is based on the solving the problem of steady-state heat conduction and allows one to eliminate the problem of convective heat exchange. The numerical implementation of this problem is divided into two stages. At the first stage, when determining the current loads of cables, the dependence of mean air temperature in the cable channel on the power of an internal heat source is determined. At the second stage, the rated current loads of cables are calculated taking into account the obtained air temperature distribution in the cable channel. In this case the problems of steady-state conduction are solved at both stages using the ANSYS software. The rated current loads of cable lines are selected by the iteration procedure taking into account the admissible insulation and shell temperatures. The performance characteristics of single conductor cables laid in the same plane and three-conductor cables with sector-shaped conductors in the cable channel have been studied.