K. Zakrzewski

Magnetic Field and Short-Circuit Reactance Calculation of the 3-Phase Transformer with Symmetrical Amorphous Core

Magnetically symmetric, 3- phase transformer has been analysed. For the two variants of the windings, the calculation results have been compared with the measured ones. Magnetic flux density components were calculated in and out of the core. The flux distribution and short-circuit reactance have been verified experimentally and a good agreement has been obtained.

Amorphous modular transformers and their 3D magnetic fields calculation with FEM

Purpose – The purpose of this paper is to examine the calculation of magnetic field distribution in the modular amorphous transformers under short‐circuit state including the flux by the voltage supplying. The magnetically asymmetrical transformer (amorphous asymmetrical transformer – AAT) has been compared also with the symmetrical one (amorphous symmetrical transformer – AST).Design/methodology/approach – 3D field problems were analyzed with total ψ and reduced ϕ potentials within the finite element method (FEM). The calculated fluxes have been verified experimentally.Findings – The field method which includes voltage excitation is helpful for flux density (B) calculation and winding reactances determination, as well. Calculations and tests yield similar flux distributions in both AST and AAT constructions. One should emphasize that AAT is better for manufacturing and repairing.Research limitations/implications – Owing to very thin (80 μm) amorphous ribbon, the solid core has been assumed for computer s...

Nonlinear scaled models in 3D calculation of transformer magnetic circuits

Purpose – To make easier and faster the designing of transformers using scale models.Design/methodology/approach – The scale modeling in designing of transformers is included. Both computer and physical models of high leakage reactance (HLR) and 3‐phase (TP3C) transformers have been considered. The 3D field computations have been executed for the scaled models, and the results were recalculated to the full‐scaled ones.Findings – It is possible to calculate the scale coefficients for nonlinear models of transformers using finite element method (FEM) software. Obtained coefficients are useful in the designing process. Measurements confirm correctness of the scaling laws.Research limitations/implications – The calculations were done only for transformers and the eddy current was not taken into account.Practical implications – Presented formulae for scale model calculation are very useful for designing of transformers by the engineers. It is possible to design a series of transformers. Only one physical model...

3‐D calculations of leakage field and reactance for special transformers

Two approaches to 3‐D magnetic field calculations for low‐power special transformers are presented in the paper. The application of fast calculation procedures based on the finite difference method, to direct solving of the Poisson and Laplace equations is given. The calculated example deals with the three‐phase leakage transformer. On the other hand, the iterative solution of regularized integral equations used for calculation of 3‐D field distribution and integral parameters of leakage field in current transformer is also presented. The software packages developed by the authors are useful for computer‐aided design of low‐power special transformers.

Electrical Engineering Committee 1990-2012

Term of office 1996-1998 Professor Tadeusz. Śliwiński, full member of Polish Academy of Sciences Chairman Professor Zbigniew Ciok, member of Polish Academy of Sciences Vice Chairman Professor Mirosław Dąbrowski, member of Polish Academy of Sciences Vice Chairman Professor Andrzej Horodecki Vice Chairman Professor Kazimierz Mikołajuk Vice Chairman Dr Hab. Eng. Tadeusz Skoczkowski Scientific Secretary

On the use of the FEM and BIE methods in the 3D magnetic field computation of the reactors with air gaps

The calculation results of the 3D magnetic field in a reactor are examined using the computer packages TRACAL3 as well as OPERA3D. The first own package is based on the boundary integral equations (BIE) and the second commercial package is deduced from finite elements method (FEM). As an example, the magnetic flux density components were calculated. For the reactors with large air gaps, the numerical results obtained by BIE and FEM are relatively close.