Iterative formulation for the skin effect on cylindrical conductors based on the Feynman's approach

2019 ◽  
Vol 33 (1) ◽  
Author(s):  
Jose Roberto Cardoso ◽  
Mauricio Barbosa Camargo Salles ◽  
Ronaldo F. Pereira ◽  
Eduardo C. Costa ◽  
Alfeu J. Sguarezi Filho
Keyword(s):  
Skin Effect ◽  
Cylindrical Conductors

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 Skin effect in rectangular conductors at high frequencies

1929 ◽  
Vol 122 (790) ◽  
pp. 533-542 ◽  
Keyword(s):  
High Frequency ◽  
Skin Effect ◽  
General Nature ◽  
Rectangular Section ◽  
Electrical Force ◽  
High Frequencies ◽  
One Dimensional ◽  
Finite Breadth ◽  
Parallel Strips ◽  
Cylindrical Conductors

There is at present little exact information either theoretical or experimental on the high frequency resistance of cylindrical conductors of rectangular section, although the general nature of the phenomenon is quite well known and has been exhaustively treated in the case of circular conductors by Kelvin, Heaviside, Russell and others. The first method of attack on the problem of the rectangular conductor is to treat it as a strip of infinite breadth when the problem becomes one dimensional and requires simply a solution of ∂ 2 E/∂ x 2 = 4πμ/ρ ∂E/∂ t E being the electrical force and μ and ρ the permeability and resistivity respectively. The solution of the problem for two parallel strips was first given by Rayleigh and it was shown that for high frequencies the current decreases exponentially toward the centre of the conductor, being confined effectively to a surface layer so that the resistance of the conductor was the same as if composed of surface strips of thickness (2πμω/ρ) -½ , ω to being the periodicity. This approximation, however, gives much too low values for the high frequency resistance of a conductor of finite breadth.

TREATMENT OF WELDED JOINTS BY A PULSE ELECTROMAGNETIC FIELD WITH SMALL SKIN-EFFECT

2018 ◽  
Vol 2018 (50) ◽  
pp. 106-114
Author(s):  
Yu. Vasetskiy ◽  
◽  
I. Kondratenko ◽  
I. Mazurenko ◽  
М. Pashchyn ◽  
...  
Keyword(s):  
Electromagnetic Field ◽  
Welded Joints ◽  
Skin Effect ◽  
Pulse Electromagnetic Field

Influence of fasteners and connections flexibility on deflections of steel building including the stressed skin effect

2018 ◽  
Vol 2 (21) ◽  
pp. 131-148 ◽  
Author(s):  
Natalia Korcz ◽  
Elżbieta Urbańska-Galewska
Keyword(s):  
Finite Elements ◽  
Skin Effect ◽  
Numerical Models ◽  
Orthotropic Shell ◽  
3D Structure ◽  
Negligible Effect ◽  
Transverse Stiffness ◽  
Shell Models ◽  
Steel Building ◽  
Two Sides

The paper presents the analysis of the influence of fasteners and connections flexibility on displacements of symmetrical single-bay pitched-roof steel building, including trapezoidal cladding acting as a diaphragm. The purpose of the article was to compare numerical models with and without taking into consideration fasteners and connections flexibility in order to observe the differences in transverse stiffness of the building during modifying model from the simple one to more complex and precise. The analyses were carried out for the 3D structure. Fasteners and connections were substituted by equivalent beam finite elements. Corrugated sheets were replaced by three types of equivalent orthotropic shell models and the influence of the choice of the model on the stiffness of the building was observed. The results showed that in the analysed structure the flexibility of fasteners and connections has negligible effect on transverse displacements of the building in the case of four sides fastening of the sheeting, however in the case of two sides fastening the influence significantly increases.

WELL TESTING HORIZONTALGAS-CONDENSATE WELLS

2017 ◽  
pp. 56-61
Author(s):  
M. L. Karnaukhov ◽  
O. N. Pavelyeva
Keyword(s):  
Comparative Analysis ◽  
Skin Effect ◽  
Horizontal Wells ◽  
Gas Condensate ◽  
Low Permeability ◽  
Well Testing ◽  
Flow Capacity ◽  
Formation Zone ◽  
Horizontal Wellbore

The well testing of gas-condensate horizontal wells are discussed in the article and the comparative analysis of borehole flow capacity, depending on the mode of it’s operation is presented. Extra attention is focused on the issue of timely identification of the reasons for the reduction of fluid withdrawal from the reservoir. The presence of high skin effect is proved, which confirms the existence of low-permeability of bottomhole formation zone related to condensation in the immediate area of the horizontal wellbore.

Modelación de Regímenes de Redes Eléctricas en Presencia de Distorsión Armónica

2017 ◽  
Vol 13 (1) ◽  
Author(s):  
I. González ◽  
S. Marrero ◽  
A. Legra ◽  
A. León
Keyword(s):  
Skin Effect ◽  
Para Determinar ◽  
La Red

En el artículo se presentan la comparación de la modelación de los elementos en las redes eléctricas en presencia de armónicos superiores de corriente y tensión. Se muestra que en el cálculo de los regímenes de trabajo de la red, resulta necesario considerar el efecto piel (Skin Effect) y las corrientes de Eddy. Al tener en cuenta estos elementos, el error en los cálculos del consumo de energía eléctrica se reduce en gran medida. Se programó una herramienta computacional (DYCSE) para determinar el flujo armónico por el método de Gauss-Seidel que fue comparado con el cálculo realizado por el software Easy Power que utiliza la técnica de inyección de corriente y así demostrar la factibilidad de uso del DYCSE a partir del grado de coincidencia en los resultados obtenidos por ambos método en un esquema patrón.

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