Magneto-thermal modeling of an encapsulated busbars system with common shield

In this paper, we propose an approach for the magnetic and thermal modeling of an encapsulated busbars system, in three-phase execution, for high voltage using QuickField software. The 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 three-phase execution busbars system with common shield. 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 electrodynamic forces that occur between conductors in the presence of the ferromagnetic shield have different values compared to those that occur in an unshielded system. In the model it was taken into account the variation of electrical conductivity with the temperature. The global heat transfer coefficient by convection and radiation used in thermal model was estimated using the power losses computed by magnetic model. When evaluating the global heat transfer coefficient was taken into account the temperature dependence of the physical properties of the air. There is a good agreement between numerical and analytical temperature values. The presented model can be used for analysis, design and optimization of three-phase busbars system with common shield.