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Article

J. Turowski

Recent progress in the development of electromagnetic field theory and sophisticated software for solution of complicated, non‐linear, 3‐D structures is not always…

Abstract

Recent progress in the development of electromagnetic field theory and sophisticated software for solution of complicated, non‐linear, 3‐D structures is not always accompanied with relatively cheap and simply presented engineering instructions, easy to use for regular industrial design. In the paper some theoretical and practical examples are given as to how one can get over a excessive calculating difficulties to obtain quickly simple design directions and reduce complicated theory to simple practical conclusions. The fast and cheap package RNM‐3D is validated by comparison with industrial test data and with the interactive graphics system is the final illustration of the effectiveness of such an approach. RNM‐3D is used successfully in many transformer works the world over.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 17 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

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Article

A.Pelikant PhD MSc

In this work author proposed complex alghorithm where field and circuit parts are strictly linked so that circuit and mechanical parameters are calculated strictly. In…

Abstract

In this work author proposed complex alghorithm where field and circuit parts are strictly linked so that circuit and mechanical parameters are calculated strictly. In this case field analysis was based on two dimmensional integrated boxes finite difference, distributions of the flux density for some excitations values and rotor positions allow to calculate some very important integral parameters, flux inkeage and the coenergy — static torque. In presented paper author show full description of the motor dynamic with the speed feed back.

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COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 13 no. 1
Type: Research Article
ISSN: 0332-1649

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Article

Patricia Penabad‐Duran, Xose M. Lopez‐Fernandez, Janusz Turowski and Pedro M. Ribeiro

The purpose of this paper is to apply a 3D methodology to assess the heating hazard on transformer covers and present a practical tool to design amagnetic inserts arrangement.

Abstract

Purpose

The purpose of this paper is to apply a 3D methodology to assess the heating hazard on transformer covers and present a practical tool to design amagnetic inserts arrangement.

Design/methodology/approach

A practical 3D methodology linking an electromagnetic analytical formulation with thermal finite element method is used for computation. Such methodology allows the evaluation of the temperature on metallic device elements heated by electromagnetic induction. This is a 3D problem which in the case of power transformers becomes especially difficult to apply due to the discretization requirement into the thin skin depth penetration compared to big machine dimensions.

Findings

From the numerical solution of the temperature field, decisions on dimensions and different amagnetic inserts arrangements can be taken to avoid hot spots on transformer covers.

Research limitations/implications

Some parameters presented in the model as heat exchange coefficients and material properties are difficult to determine from formulae or from the literature. The accuracy of the results strongly depends on the proper identification of those parameters, which the authors adjust based on measurements.

Originality/value

Differing from previous works found in the literature, which focus their results in power loss computation methods, this paper evaluates losses in terms of temperature distribution, which is easier to measure and validate over transformer covers. Moreover, an experimental work is presented where the temperature distribution is measured over a steel cover plate and a cover plate with amagnetic insert.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 31 no. 2
Type: Research Article
ISSN: 0332-1649

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Article

S. Wiak, A. Pelikant and J. Turowski

This paper presents the numerical solution of the TEAM Workshop Problem 7 obtained by Reluctance Network Method (RNM). The problem represents a three‐dimensional multiply…

Abstract

This paper presents the numerical solution of the TEAM Workshop Problem 7 obtained by Reluctance Network Method (RNM). The problem represents a three‐dimensional multiply connected eddy current problem with a time — harmonic excitation. The numerical results obtained by RNM in reasonable computing time, agree extremely well with experimental data and other methods results.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 13 no. 1
Type: Research Article
ISSN: 0332-1649

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Article

S. Wiak, A. Pelikant and J. Turowski

Magnetostaic field analysis of 3‐D nonlinear model problem (No.10 ‐ TEAM Workshop) is carried out by the authors using the Reluctance Network Method. The components and…

Abstract

Magnetostaic field analysis of 3‐D nonlinear model problem (No.10 ‐ TEAM Workshop) is carried out by the authors using the Reluctance Network Method. The components and resultant flux density are computed and compared with measurements and results obtained by other authors and shaw reasonable convergence and much less CPU time.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 11 no. 1
Type: Research Article
ISSN: 0332-1649

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Article

A. Pelikant and J. Turowski

Heavy current bushings passing through steel cover plates and housing walls of power transformers, generators and other large power equipment are thermally hazardous…

Abstract

Heavy current bushings passing through steel cover plates and housing walls of power transformers, generators and other large power equipment are thermally hazardous elements of construction and a source of additional power losses. Safety and reliability of such expensive objects and safety of power delivery often depend on the proper design of these elements. In the paper a computer analysis, based on Maxwell equations and analytical representation of electromagnetic field was carried out. Non‐linear permeability of solid steel was considered with the help of analytical approximation. Eddy current losses have been calculated and compared using different methods of calculation and experiments. The method of forecasting possible excessive heating and hot spot with the help of electromagnetic criteria was used. Various constructional means of loss and hot spot reduction were proposed and examined.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 17 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

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Article

Adam Pelikant, Sl§awomir Wiak and Krzysztof Kome5za

This paper presents the results of silicon micromotor static and dynamic simulations by means of finite element method and the Moulton‐Adams algorithm as well. Capacitance…

Abstract

This paper presents the results of silicon micromotor static and dynamic simulations by means of finite element method and the Moulton‐Adams algorithm as well. Capacitance and torque curves calculation. The virtual work principle has been applied. The dynamic states of the motor are described by the non‐linear and non‐stationary system of ordinary difference equations solved numerically. Some results of computer simulation of dynamic states are presented and discussed.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 17 no. 3
Type: Research Article
ISSN: 0332-1649

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Article

Patricia Penabad Durán, Paolo Di Barba, Xose Lopez-Fernandez and Janusz Turowski

The purpose of this paper is to describe a parameter identification method based on multiobjective (MO) deterministic and non-deterministic optimization algorithms to…

Abstract

Purpose

The purpose of this paper is to describe a parameter identification method based on multiobjective (MO) deterministic and non-deterministic optimization algorithms to compute the temperature distribution on transformer tank covers.

Design/methodology/approach

The strategy for implementing the parameter identification process consists of three main steps. The first step is to define the most appropriate objective function and the identification problem is solved for the chosen parameters using single-objective (SO) optimization algorithms. Then sensitivity to measurement error of the computational model is assessed and finally it is included as an additional objective function, making the identification problem a MO one.

Findings

Computations with identified/optimal parameters yield accurate results for a wide range of current values and different conductor arrangements. From the numerical solution of the temperature field, decisions on dimensions and materials can be taken to avoid overheating on transformer covers.

Research limitations/implications

The accuracy of the model depends on its parameters, such as heat exchange coefficients and material properties, which are difficult to determine from formulae or from the literature. Thus the goal of the presented technique is to achieve the best possible agreement between measured and numerically calculated temperature values.

Originality/value

Differing from previous works found in the literature, sensitivity to measurement error is considered in the parameter identification technique as an additional objective function. Thus, solutions less sensitive to measurement errors at the expenses of a degradation in accuracy are identified by means of MO optimization algorithms.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 34 no. 2
Type: Research Article
ISSN: 0332-1649

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Article

Adam Warzecha

Electrical machines with nonlinear magnetic circuits are usually modelled by coupling magnetic and electric equations using software for magnetic field investigation…

Abstract

Electrical machines with nonlinear magnetic circuits are usually modelled by coupling magnetic and electric equations using software for magnetic field investigation. These hybrid methods are practically effective only for steady states, due to their time‐consuming calculations. The separation of both sets of equations will be possible if the unique relationships between linked fluxes and all armature currents become determined. It needs, of course, the neglect of the eddy‐currents in the machine rotor. Generally, they are defined as the partial derivatives of coenergy:

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 14 no. 4
Type: Research Article
ISSN: 0332-1649

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Article

Zbigniew Gmyrek and Grzegorz Zwoliński

The commonly used power electronic systems in the drives of electrical machines as well as in the nonlinear receivers, being the transformer’s load, are the main origin of…

Abstract

The commonly used power electronic systems in the drives of electrical machines as well as in the nonlinear receivers, being the transformer’s load, are the main origin of the deformation in the voltage supply. Due to these, the voltage curve is not sinusoidally variable. In these cases additional power losses take place in the motor and transformer cores which occur due to higher order harmonics of the flux. This paper presents a method to determine the power losses for the core where there are two fluxes in the steel sheet: one with relatively small amplitude and high frequency, and the other one with relatively large amplitude but low frequency.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 20 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

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