Simulation of cooling enhancement in industrial low-voltage switchgear using validated coupled CFD-EMAG model

The paper presents an advanced numerical study of industrial switchgear with the joint electric resistance included. The fundamental thermal problems (radiation, convection and conduction) in copper busbars, supporting parts and cooling air were coupled with the electromagnetic field to accurately define the power losses. The mathematical model was based on the validated model of the simplified laboratory switchgear. However, more sophisticated busbar system was employed in this study. The model results were compared with the measurements data for two switchgear configurations of different type of a top cover, i.e. ventilated and solid ones. Then, the “what-if” studies for basic configuration were considered. In the considered problem, the influence of the busbar surface emissivity modification, the changes in enclosure inlet/outlet grids and application of the radiator without fan on the local and global temperature reduction within the switchgear was analysed. The results obtained show the importance of radiative heat transfer and emphasize the influence of the surface emissivity in the switchgear cooling process.