Modeling of a magnetic shunt and an aluminum screen using the perturbation finite element method

In this paper the perturbation technique is developed for modeling of the magnetic shunt and an aluminum screen in large power transformers. The problem is first studied using either a simplified analytical or a finite element model. A more elaborated model is then defined to take into account its structural details. The calculation of iron losses and of the minimum clearance between bus bars leading current and magnetizable steel parts for a frequency range is performed. The modeling takes into account the eddy currents in magnetic shunt laminations due to the magnetic field in the shunt.