The Computation of Winding Eddy Losses in Power Transformers Using Analytical and Numerical Methods (original) (raw)
Related papers
Practical Wide Frequency Approach for Calculating Eddy Current Losses in Transformer Windings
2006 IEEE International Symposium on Industrial Electronics, 2006
A practical method for calculating eddy current losses in transformer windings is reported. The method improves the classical loss presentation by introducing a loss coefficient, called eddy current factor k c. In this paper, eddy current losses in round conductors are discussed. A graphical approximation of k c as a function of wire diameter, frequency, layer number, copper packing factors in the direction parallel and perpendicular to the layer is provided. The graphs are obtained by analytical expressions compared with FEM simulations. To unify the approach for different cases, a reference diameter, apparent and equivalent frequency are defined. A few short examples for applying the method in transformer design are given. The method is applicable for a variety of transformers with different frequencies, wire diameters and conductor fittings. The proposed method is verified by designing several transformers. As an example, a 2.5 kW transformer is fully described. The experiments show good matching with the calculations.
Improved Graphical Method for Calculation of Winding Losses in Transformers
2004
We report an improved method for calculating eddy current losses in round wires of magnetic components. The method extends the classical loss presentation by defining a loss coefficient, called eddy current factor kc. The effects of the fields of eddy currents in wires and the local fields (not only transverse fields) are considered. We provide a graphical approximation of kc as a function of wire diameter, frequency, layer number, copper packing factors in the direction parallel and perpendicular to the layer. The graphs are obtained by analytical expressions compared with FEM simulations. A reference diameter, equivalent frequency and resistivity are used to unify the approach for different cases.
A Novel Approach for Evaluating Eddy Current Loss in Wind Turbine Generator Step-Up Transformers
Advances in Science, Technology and Engineering Systems Journal, 2021
South Africa is aiming to achieve a generation capacity of about 11.4GW through wind energy systems, which will contribute nearly 15.1% of the country's energy mix by 2030. Wind energy is one of the principal renewable energy determinations by the South African government, owing to affluent heavy winds in vast and remote coastal areas. In the design of newfangled Wind Turbine Generator Step-Up (WTGSU) transformers, all feasible measures are now being made to drive the optimal use of active components with the purpose to raise frugality and to lighten the weight of these transformers. This undertaking is allied with numerous challenges and one of them, which is particularly theoretical, is delineated by the Eddy currents. Many times the transformer manufacturer and also the buyer will be inclined to come to terms with some shortcomings triggered by Eddy currents. Still and all, it is critical to understand where Eddy currents emanate and the amount of losses and wherefore the temperature rise that may be produced in various active part components of WTGSU transformers. This is the most ideal choice to inhibit potential failure of WTGSU transformers arising from excessive heating especially under distorted harmonic load conditions. In the current work, an extension of the author's previous work, new analytical formulae for the Eddy loss computation in WTGSU transformer winding conductors have been explicitly derived, with appropriate contemplation of the fundamental and harmonic load current. These formulae allow the distribution of the skin effect and computation of the winding Eddy losses as a result of individual harmonics in the winding conductors. These results can be utilized to enhance the design of WTGSU transformers and consequently minimize the generation of hotspots in metallic structures.
D Calculation and Modeling of Eddy Current Losses in a Large Power Transformer A. M. Milagre
Elimination of hot spots and reduction of eddy current losses in structural parts is one of the important constituents of transformer design. In this work, the eddy current losses in the clamping frame, transformer tank and electromagnetic shielding are calculated using a 3D finite element method. The clamping frame, transformer tank and electromagnetic shielding are modeled by surface impedance method. The paper analyses the effects of electromagnetic shielding and magnetic shunts on the eddy current loss reduction in the transformer tank. Index Terms – Eddy current losses, finite element method, power transformer.
Evaluation of eddy current losses in the cover plates of distribution transformers
IEE Proc. Sci. Meas. Technol., 2004
The elimination of hot spots and the reduction of eddy current losses in bushing mounting plates is an important consideration in transformer design. The currently used bushing mounting plates are either mild steel plates, or mild steel plates with non-magnetic stainless steel inserts or stainless steel plates. The authors calculate the eddy current losses in bushing mounting plates using four different methods; (i) an analytical formulation; (ii) a three-dimensional finite element method (FEM); (iii) from measured values of the initial temperature rise; and (iv) from measured values of the steady-state temperature rise. There is a close agreement between the loss values obtained using these four methods. The analysis has resulted in a detailed understanding of the loss pattern and temperature rise phenomenon in bushing mounting plates. The authors also analyse tank plates of small pad-mounted distribution transformers. It is shown that judicious use of non-magnetic stainless steel can result in considerable energy savings for pad-mounted transformers. FEM simulations are performed to find out cost-effective materials for the tank plates of the pad-mounted transformers. A T-shaped stainless steel plate is found to significantly reduce the load loss. The results of the simulations have been verified on a 225 kVA pad-mounted transformer.
IEEE Transaction on Magnetics, 2014
This paper presents a new and rigorous analytical calculation of electromagnetic field and eddy current losses in the zones of transformer tanks where bushings are mounted. This is done by solving Maxwell’s equations in the regions surrounding bushings, with the corresponding boundary conditions and considering linear permeability. Then, by solving the modified Bessel´s equation the analytical formulae to calculate the magnetic field and eddy current losses in these regions are obtained and several cases are studied. The results are compared with 3D Finite Element simulations and show very close correspondence. The obtained formulae allow straightforward calculations that can help designers to select proper parameters to optimize the design of transformers. This paper can be taken as the basis for the analysis of the nonlinear permeability case.
Analysis of Losses in Power Transformer
This paper examined and presented a simplified approach to power transformer design. Analyzed possible losses associated with power transformers through computational techniques and crucial design diagram.
A Review of Transformer Losses
Electric Power Components and Systems Journal (Taylor & Francis), 2009
This article presents an extensive survey of current research on the transformer loss problem, particularly from the view of practical engineering applications. It reveals that the transformer loss problem remains an active research area. This article classified the transformer loss problem into three main groups: (a) tank losses due to high-current bushings, (b) losses in transformer core joints, and (c) stray losses in the transformer tank. It is based on over 50 published works, which are all systematically classified. The methods, the size of transformers, and other relevant aspects in the different works are discussed and presented.