Summary

Accurate estimation of cable ampacity is of vital importance as it allows a better utilization of power cables while avoiding thermal degradation and potential failure. IEC 60287-2-3 is a recently developed standard for fast estimation of ampacity of cables in ventilated tunnels, its novelty being inclusion of longitudinal convective heat transfer. However, convective heat transfer is notoriously difficult to both model and characterize, which raises questions regarding the accuracy of the standard’s simplified analytic equations. In this paper, the standard is evaluated against experimental data for a single cable and for a flat configuration of three cables placed on the floor of a trough. The results show that the standard accurately estimates conductor temperatures under conditions without ventilation, whereas significant deviations occur under forced ventilation. Specifically, longitudinal convective heat transfer is underestimated for forced laminar air flow, while it is significantly overestimated under turbulent air flow.

Additional informations

Publication type Session Materials
Reference B1_11866_2026
Publication year
Publisher CIGRE
Country Norway
Study committees
File size 2 MB
Price for non member 30 €
Price for member 30 €

Authors

HELLESØ Svein M. - SINTEF Energy; THINN Kristian S. - SINTEF Energy; EBERG Espen - SINTEF Energy; MELLERUD Runar F. - SINTEF Energy

Keywords

Ampacity, Convective cooling, Cable rating, Cable trough, Forced ventilation.

Cables in ventilated conduits: experimental and numerical study of heat transfer and cable ratings