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Article
Publication date: 4 January 2016

J. Faiz, H. Ehya, A.M. Takbash, S. Shojaee, M. Hamidian and A. Ghorbani

Electrical energy distribution systems must be low losses systems in order to enhance the system efficiency. Therefore, it is preferred to distribute electrical energy by…

229

Abstract

Purpose

Electrical energy distribution systems must be low losses systems in order to enhance the system efficiency. Therefore, it is preferred to distribute electrical energy by bus-ducts in the place of cables over all energy levels and decrease the losses. The purpose of this paper is to focus on a comprehensive survey of various aspects of bus-ducts design including electromagnetic, mechanical and thermal. Advantages and disadvantages of different available design techniques are reviewed.

Design/methodology/approach

Different works on various bus-based power transmission and distribution systems are reviewed. Generally these are done in three categories including systems modeling methods, heat transfer in the systems, short circuit and electromagnetic force. The attempt is made to provide geometrical and materials specifications in order to present the analyzed system well.

Findings

Different types of bus-ducts from used materials, voltage level and insulation types are reviewed. Bus-duct modeling techniques are introduced which can be easily applied for bus-ducts design. Electromagnetic field distribution, thermal pattern inside and outside of the bus-duct in normal and short circuit modes and finally mechanical considerations are dominant factors which must be taken into account in the bus-ducts design. This leads to an optimal design of bus-ducts which prolong the life span of the bus-ducts fixed in the installations.

Originality/value

This paper for the first time systematically reviews the latest state of arts in the design of bus-ducts for efficient electrical energy distribution. It summarizes a variety of design techniques applicable to bus-ducts design.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 35 no. 1
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 7 November 2016

Manuel Pineda-Sanchez, Angel Sapena-Baño, Juan Perez-Cruz, Javier Martinez-Roman, Ruben Puche-Panadero and Martin Riera-Guasp

Rectangular conductors play an important role in planar transmission line structures, multiconductor transmission lines, in power transmission and distribution systems, LCL…

280

Abstract

Purpose

Rectangular conductors play an important role in planar transmission line structures, multiconductor transmission lines, in power transmission and distribution systems, LCL filters, transformers, industrial busbars, MEMs devices, among many others. The precise determination of the inductance of such conductors is necessary for their design and optimization, but no explicit solution for the AC resistance and internal inductances per-unit length of a linear conductor with a rectangular cross-section has been found, so numerical methods must be used. The purpose of this paper is to introduce the use of a novel numerical technique, the proper generalized decomposition (PGD), for the calculation of DC and AC internal inductances of rectangular conductors.

Design/methodology/approach

The PGD approach is used to obtain numerically the internal inductance of a conductor with circular cross-section and with rectangular cross-section, both under DC and AC conditions, using a separated representation of the magnetic vector potential in a 2D domain. The results are compared with the analytical and approximate expressions available in the technical literature, with an excellent concordance.

Findings

The PGD uses simple one-dimensional meshes, one per dimension, so the use of computational resources is very low, and the simulation speed is very high. Besides, the application of the PGD to conductors with rectangular cross-section is particularly advantageous, because rectangular shapes can be represented with a very few number of independent terms, which makes the code very simple and compact. Finally, a key advantage of the PGD is that some parameters of the numerical model can be considered as additional dimensions. In this paper, the frequency has been considered as an additional dimension, and the internal inductance of a rectangular conductor has been computed for the whole range of frequencies desired using a single numerical simulation.

Research limitations/implications

The proposed approach may be applied to the optimization of electrical conductors used in power systems, to solve EMC problems, to the evaluation of partial inductances of wires, etc. Nevertheless, it cannot be applied, as presented in this work, to 3D complex shapes, as, for example, an arrangement of layers of helically stranded wires.

Originality/value

The PGD is a promising new numerical procedure that has been applied successfully in different fields. In this paper, this novel technique is applied to find the DC and AC internal inductance of a conductor with rectangular cross-section, using very dense and large one-dimensional meshes. The proposed method requires very limited memory resources, is very fast, can be programmed using a very simple code, and gives the value of the AC inductance for a complete range of frequencies in a single simulation. The proposed approach can be extended to arbitrary conductor shapes and complex multiconductor lines to further exploit the advantages of the PGD.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 35 no. 6
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 28 March 2019

Jerzy Gołębiowski and Marek Zaręba

The purpose of this paper is to analyse the dynamics of a thermal field generated in a tubular bus with rated current by using two models of electrical resistivity of copper.

80

Abstract

Purpose

The purpose of this paper is to analyse the dynamics of a thermal field generated in a tubular bus with rated current by using two models of electrical resistivity of copper.

Design/methodology/approach

The boundary-initial problem of the modified heat equation was formulated for the tubular bus. Analytical solutions were obtained by means of Green’s functions as the kernels of the integral operator inverse to the corresponding differential operator. The results were presented graphically and verified using the finite element method. The calculations were made by considering the example of the Storm Power Components tubular bus (USA).

Findings

Analytical field models were used to determine time- and space-variable heating curves, time constants and steady-state current ratings.

Research limitations/implications

This paper is related to the structure of a hollow cylinder. Other bus sections can be taken into account by using the coordinate systems of different curvilinear orthogonal symmetry.

Originality/value

Using the analytical method, the influence of the variable (temperature dependent) electrical resistivity on some important parameters and characteristics of the tubular bus was investigated. The system was considered as an element with distributed parameters.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 38 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

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Article
Publication date: 5 January 2022

Wissam Dehina, Mohamed Boumehraz, Wissam Dehina and Frédéric Kratz

The purpose of this paper is to propose applications of advanced signal-processing techniques for the diagnosis and detection of rotor fault in an induction machine. Two…

120

Abstract

Purpose

The purpose of this paper is to propose applications of advanced signal-processing techniques for the diagnosis and detection of rotor fault in an induction machine. Two techniques are used: spectral analysis techniques and time frequency techniques for the diagnosis of an electrical machine. One is based on the power spectral density estimation techniques, such as periodogram and Welch periodogram. The second method is based on Hilbert transform (HT) to extract the envelope for the stator current. Then, this signal is processed via discrete wavelet transform (DWT) for determining the faulty components in the spectrum of the stator current envelope and identifying the eigenvalues of energies (HDWT).

Design/methodology/approach

First, this paper focused on theoretical development and a comparative study of these signal-processing techniques, which are based on the periodogram, Welch periodogram, HT and the DWT to extract the envelope for the stator current; it is used to compute the energy stored in each decomposition level obtained by the stator current envelope (HDWT). Moreover, the Welch periodogram is applied to obtain the envelope spectrum.

Findings

The simulation obtained and the experimental validation results of the proposed methods through MATLAB environment show the effectiveness of the proposed approaches with a good accuracy by power spectral density estimation techniques (periodogram and Welch periodogram). Moreover, the faults are manifested through the appearance of new frequencies components, as well as the envelope for the stator current (HT and DWT). This approach is effective for non-stationary and stationary signal to extract useful information for the detection of broken bar fault.

Originality/value

The current paper proposes a new diagnosis method for the detection and characterization of broken rotor bars defects early; it is founded primarily on theoretical development, and the comparison is based on the power spectral density technique (periodogram and Welch periodogram) and the computation of the energy stored in each decomposition level (precisely the HT and DWT). Moreover, the Welch periodogram is applied to obtain the envelope spectrum. The main advantages of the proposed techniques increase their reliability and availability.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 41 no. 5
Type: Research Article
ISSN: 0332-1649

Keywords

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Article
Publication date: 5 September 2016

Ying Xie, Ze Wang, Xueting Shan and Yangyang Li

Thermal stress of the rotor in a squirrel cage induction motor is generated due to the temperature rise, and the structure of the rotor will be destroyed if the stress acted on…

207

Abstract

Purpose

Thermal stress of the rotor in a squirrel cage induction motor is generated due to the temperature rise, and the structure of the rotor will be destroyed if the stress acted on the rotor exceeds its limits, so the thermal stress is also one of the main causes led to broken bar fault. The purpose of this paper is to report the thermal stress coupled analysis for the induction motor with healthy and faulty rotor, and to find the variation tendency of the temperature and thermal stress due to broken bars, and the part most likely to break in the rotor as a result of the thermal stress load are identified.

Design/methodology/approach

The steady temperature and thermal stress of the rotor in the case of the healthy and faulty conditions are calculated by finite element method, and the 3D model of the motor used in the experiments is established and the experimental results are presented for both healthy and faulty machines.

Findings

The influence of the broken bars fault on the motor thermal profile and thermal stress can be found, and it explains why the breaking point always appears in the joint of the bars and end rings.

Originality/value

The paper presents the 3D thermal stress coupled model and performance characteristics of induction motor with broken bars. The reasonable constraint is established according to the contact of components each other, and more reasonable fracture location is selected. The results obtained by the simulation model are in a good agreement with practical situation, because the effect of skewed rotor were taken into consideration in the process of simulation.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 35 no. 5
Type: Research Article
ISSN: 0332-1649

Keywords

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