Thermal modeling and experimental validation of an encapsulated busbars system

In this paper, we propose an approach for the magnetic and thermal modeling of an encapsulated busbars system for high voltage using QuickField software. This paper proposes a numerical model developed by coupling of the magnetic field problem with the stationary and transient heat field problems for the geometry of a single-phase execution busbars system. The coupling of problems is realized by importing specific losses from the magnetic field problem as heat sources for thermal field problem. The magnetic field problem is also coupled to the electrical circuit. The shields are short-circuited at both ends and they are connected to the ground. For this constructive solution, in the shields occur induced currents, approximately equals to those of conductors. Due to the shielding effect, the magnetic field is practically zero outside of shield and therefore the electrodynamic forces do not occur between phases. In the model it was taken into account the variation of electrical conductivity with the temperature. The thermal model has been validated by experiment. The global coefficient of heat transfer by convection and radiation used in thermal model was estimated using the power losses computed by magnetic model. There is a good agreement between numerical and experimental temperature values. The presented model can be used for analysis, design and optimization of three-phase busbars system in single phase execution.