3D MAGNETIC-FIELD DISTRIBUTION OF YOKE FLUX IN 3-PHASE TRANSFORMERS WITHOUT FERROMAGNETIC TANKS

The 3D calculation of the monophase flux, due to n-triple harmonics of the windings currents is considered. For small, three-phase transform ers without ferromagnetic tanks the calculation consists in unbounded problem solution. The 3D magnetic field of the yoke flux outside the m agnetic core was analysed numerically by means of integral equations m ethod. Our computer program subroutines, written in Fortran 77, have b een implemented to a personal computer. The calculated components of t he magnetic flux density were compared with the measured ones. The dis tribution of the different flux parts was calculated and tested by mea surements for a three-phase transformer.