Enhanced method for pulse skin effect calculation of cylindrical conductors

2020 ◽  
Vol 39 (3) ◽  
pp. 623-635
Author(s):  
Nebojsa B. Raicevic ◽  
Slavoljub R. Aleksic ◽  
Ilona Iatcheva ◽  
Marinko Barukcic
Keyword(s):  
Electromagnetic Field ◽  
Density Distribution ◽  
Cross Section ◽  
Current Density ◽  
Skin Effect ◽  
Current Density Distribution ◽  
Accurate Solution ◽  
Lightning Strike ◽  
Content Type ◽  
Cylindrical Conductors

Purpose This paper aims to present a new approach to the numerical solution of skin effect integral equations in cylindrical conductors. An approximate, but very simple and accurate method for calculating the current density distribution, skin-effect resistance and inductance, in pulse regime of cylindrical conductor, having a circular or rectangular cross-section, is considered. The differential evolution method is applied for minimization of error functional. Because of its application in the practice, the lightning impulse is observed. Direct and inverse fast Fourier transform is applied. Design/methodology/approach This method contributes to increasing of correctness and much faster convergence. As the electromagnetic field components depend on the current density derivation, the proposed method gives a very accurate solution not only for current density distribution and resistance but also for field components and for internal inductance coefficients. Distribution of current and electromagnetic field in bus-bars can be successfully determined if the proximity effect is included together with the skin effect in calculations. Findings The study shows the strong influence of direct lightning strikes on the distribution of electrical current in cables used in lightning protection systems. The current impulse causes an increase in the current density at all points of the cross-section of the conductor, and in particular the skin effect on the external periphery. Based on the data calculated by using the proposed method, it is possible to calculate the minimum dimensions of the conductors to prevent system failures. Research limitations/implications There are a number of approximations of lightning strike impulse in the literature. This is a limiting factor that affects the reliability and agreement between measured data with calculated values. Originality/value In contrast with other methods, the current density function is approximated by finite functional series, which automatically satisfy wave equation and existing boundary conditions. It is necessary to minimize the functional. This approach leads to a very accurate solution, even in the case when only two terms in current approximation are adopted.

scholarly journals INFLUENCE OF SKIN EFFECT ON THE CALCULATION OF BUSBAR SYSTEMS HAVING RECTANGULAR CROSS SECTION

2021 ◽  
Vol 20 (1) ◽  
pp. 057
Author(s):  
Nebojša Raičević ◽  
Ana Vučković ◽  
Mirjana Perić ◽  
Slavoljub Aleksić
Keyword(s):  
Electromagnetic Field ◽  
Cross Section ◽  
Current Density ◽  
Proximity Effect ◽  
Skin Effect ◽  
Rectangular Cross Section ◽  
Error Function ◽  
Current Density Distribution ◽  
Accurate Solution ◽  
Flow Through

One method for the calculation of current density distribution in a finite number of long parallel conductors, having rectangular cross section, is proposed in this paper. Numerical results aim to highlight the importance of the skin effect, which can be combined with the proximity effect. The method of superposition of these two effects was applied to the calculation of the electromagnetic field in electric power busbars systems. It has been shown that the skin effect has a much greater impact, especially when the conductors are thin and strong electric currents flow through them, so special attention is paid to its calculation. For numerical solution the integral equations are used. The function of current density is approximated by the finite functional series. This way leads to a very accurate solution with only two terms. Differential evolution method is applied for minimization of error function. To demonstrate the application of the proposed approach, numerical values for busbars are presented and compared with values obtained by using the finite elements method.

scholarly journals Inductance gradient and current density distribution for T-shaped convex and concave rail cross-sections

2018 ◽  
Vol 7 (1.8) ◽  
pp. 237
Author(s):  
M. N. Saravana Kumar ◽  
R. Murugan ◽  
Poorani Shivkumar
Keyword(s):  
Density Distribution ◽  
Cross Section ◽  
Cross Sections ◽  
Current Density ◽  
Current Density Distribution ◽  
Design Parameters ◽  
Element Analysis ◽  
Analysis Technique ◽  
Section Shape ◽  
Uniform Current

Rectangular rail was the most widely used cross section shape for the rail gun electromagnetic launching (EML) system. Based on sector assimilation, the rail gun key parameter especially current density (J) and inductance gradient (L’) greatly affected. J decides the efficiency of EML and L’ decides the force acting on the projectile of EML. So, it is mandatory to look upon the sector assimilation of rails. In this paper T shape convex and concave shape rail cross section is proposed and rail gun key design parameters are calculated by varying its dimensions using Ansoft Maxwell 2-D eddy current solver which uses finite element analysis technique to calculate these parameters. The performance of rail gun discussed using the obtained values and it has been observed and that the compared with other considered rail geometries, the T-shaped concave model shows more impact on inductance value which causes uniform current density distribution over the rails.

Visualization of spatial conductivity irregularities within conductive rubber sheets

2016 ◽  
Vol 35 (4) ◽  
pp. 1393-1402 ◽  
Author(s):  
Helmut Wernick ◽  
Patrick Hoelzl ◽  
Bernhard G. Zagar
Keyword(s):  
Magnetic Field ◽  
Density Distribution ◽  
Current Density ◽  
Measurement Method ◽  
Current Density Distribution ◽  
Contactless Measurement ◽  
Rubber Sheet ◽  
Content Type ◽  
Conductivity Distribution ◽  
Conductive Rubber

Purpose – The purpose of this paper is to present a fast and contactless measurement method to determine the spatial conductivity distribution within an intrinsically conducting polymer, more precisely a conductive rubber sheet specimen. As a consequence of the manufacturing process and the material composition, the conductivity distribution within the sheet is assumed to be inhomogeneous. Design/methodology/approach – The current density distribution within the conductive rubber sheet due to an excitation current is estimated from the measured magnetic field distribution. Therefore, a GMR sensor is used to spatially sample the magnetic field above the specimen. Based on the estimated current density distribution and alternatively the local power dissipation calculated from a thermal image, the conductivity distribution within the specimen is determined. For comparison a reference measurement with a classical resistivity probe is done. Findings – The measurement results show a good agreement between the developed and the classical method. Moreover, the developed measurement method requires less time and still offers a higher spatial resolution. Originality/value – The presented results demonstrate the potential of the developed measurement method for determining the conductivity distribution within thin and planar specimens. Furthermore, conclusions can be drawn about the material homogeneity of the used test specimen.

scholarly journals Analytical magnetic field calculation for flat permanent-magnet linear machines with dual-rotor by using improved two-dimensional hybrid analytical method

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Brahim Ladghem Chikouche ◽  
Kamel Boughrara ◽  
Dubas Frédéric ◽  
Rachid Ibtiouen
Keyword(s):  
Magnetic Field ◽  
Density Distribution ◽  
Relative Permeability ◽  
Current Density ◽  
Analytical Method ◽  
Maxwell’S Equations ◽  
Maxwell's Equations ◽  
Current Density Distribution ◽  
Two Dimensional ◽  
Content Type

Purpose This paper aims to propose an improved two-dimensional hybrid analytical method (HAM) in Cartesian coordinates, based on the exact subdomain technique and the magnetic equivalent circuit (MEC). Design/methodology/approach The magnetic field solution is obtained by coupling an exact analytical model (AM), calculated in all regions having relative permeability equal to unity, with a MEC, using a nodal-mesh formulation (i.e. Kirchhoff’s current law) in ferromagnetic regions. The AM and MEC are connected in both axes (x, y) of the (non-)periodicity direction (i.e. in the interface between the tooth regions and all its adjacent regions as slots and/or air-gap). To provide accuracy solutions, the current density distribution in slot regions is modeled by using Maxwell’s equations instead of the MEC characterized by an equivalent magnetomotive force (MMF) located in slots, teeth and yokes. Findings It is found that whatever the iron core relative permeability, the developed HAM gives accurate results for no- and on-load conditions. The finite-element analysis demonstrates excellent results of the developed technique. Originality/value The main objective of this paper is to make a direct coupling between the AM and MEC in both directions (i.e. x- and y-edges). The current density distribution is modeled by using Maxwell’s equations instead of the MEC and characterized by an MMF.

Numerical simulation and experiments to improve throwing power for practical PCB through-holes plating

Circuit World ◽  
2019 ◽  
Vol 45 (4) ◽  
pp. 221-230
Author(s):  
Jing Xiang ◽  
Chong Wang ◽  
Yuanming Chen ◽  
Feng Xia ◽  
Wei He ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Density Distribution ◽  
Electrochemical Properties ◽  
Current Density ◽  
Cell Model ◽  
Current Density Distribution ◽  
Circuit Board ◽  
Convection Current ◽  
Throwing Power ◽  
Content Type

Purpose The purpose of this study is to investigate the synergism of convection, current density distribution and additives by numerical simulation and electrochemical experiments for good throwing power (TP) of copper electro-deposition in printed circuit board (PCB) manufacture. Design/methodology/approach The flow field of THs and current density distribution on various AR of THs are calculated and analyzed. Meanwhile, corresponding simulation is used to study the performance of plating electrolytes on TP. Two electrochemical parameters, overpotential (η) and potential difference (△η), are chosen to evaluate the electrochemical properties of different plating solutions by galvanostatic measurement and potentiodynamic cathode polarization at different rotating speeds. Findings By combining both the results of simulation and practical plating, these two electrochemical properties of electrolytes exhibit significant impact to the system at varied conditions. Especially, the electrolyte with higher polarizing η and △η values lead to the elevated TP for AR of more than 2:1. Originality/value The harring cell model is built as a bridge between the theoretical and experimental study for control of uniformity of plating THs in PCB manufacturing. This dual-parameter evaluation is validated to be a promising decisive method to guide the THs plating with particular AR in industry.

Insitu SVET studies on the current density distribution on dissolving of Mg, MgZn2, Mg2Si and Al4Cu2Mg8Si7 surfaces in NaCl solutions

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Alexander I. Ikeuba ◽  
Peter C. Okafor ◽  
Benedict Ita ◽  
Anthony I. Obike ◽  
Fidelis E. Abeng ◽  
...  
Keyword(s):  
Density Distribution ◽  
Current Density ◽  
Auxiliary Information ◽  
Current Density Distribution ◽  
Sample Surface ◽  
Corrosion Monitoring ◽  
Content Type ◽  
Current Densities ◽  
Phase Surface ◽  
Electrode Technique

Purpose This paper aims to acquire the current density distribution on dissolving of Mg, MgZn2 (η -phase), Mg2Si (ß-phase) and Al4Cu2Mg8Si7 (Q-phase) surface in NaCl solutions. Design/methodology/approach MgZn2 (η -phase), Mg2Si (ß-phase) and Al4Cu2Mg8Si7 (Q-phase) are important intermetallic compounds found in aluminum alloys. Insitu scanning vibrating electrode technique (SVET) was used to acquire the current density distribution on dissolving of Mg, MgZn2 (η -phase), Mg2Si (ß-phase) and Al4Cu2Mg8Si7 (Q-phase) surface in NaCl solutions scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX) was used to characterize the corroded surface. Findings SVET maps reveal that these compounds display characteristic dissolution features. Mg and MgZn2 displayed localized anodic and cathodic sites while that of Al4Cu2Mg8Si7 > Mg2Si displayed a diffused distribution of anodic and cathodic sites. The magnitude of the integrated anodic current densities on the compounds was noted to decrease with the progress of time, and the order of the magnitude of the current density with respect to the compounds is Mg > Mg2Si > Al4Cu2Mg8Si7 > MgZn2. SEM/EDX reveal that the highest mass loss recorded after the SVET test was manifested by Mg2Si followed by MgZn2 then Al4Cu2Mg8Si7. Originality/value Auxiliary information on the current density distribution on the corroding sample surface at the microscopic scale has been provided by SVET thereby taking care of certain limitations of traditional corrosion monitoring techniques such as gravimetric, hydrogen evolution and electrochemical measurements.

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