The effect of nonlinear loads on the underground distribution cables: a case study

Abstract

Nonlinear loads have become more prevalent in all applications, including computers, transformers, and adjustable speed drives. The harmonic level of the underground distribution cables rises as a result of these loads. As a result, the cable layers' temperatures are affected by the harmonic levels. The purpose of this paper is to calculate the temperature distribution of a cable conductor and the soil around it under cyclic loading conditions, including the impact of linear and nonlinear loads. The IEC 60,853-2 standard is used to consider the thermal model of an underground cable. The finite element method is investigated to obtain a heat map of the cable layers and their surrounding soil. In this study, the small-scale model was constructed in the laboratory. The cable is installed using two methods at the same loading conditions. The heat transfer in the four-core low-voltage cable installation is measured. Furthermore, total harmonic distortion is measured using a Fluke 125 scope meter. The experimental results from the laboratory model proved that there was an extreme increase in the temperature of cable layers when the cable was installed inside the polyvinyl chloride duct in the soil compared with its installation directly buried in the soil. The results of the experimental tests are compared with simulation results.