Metallic electrodes are widely used in many applications, the analysis of their frequency-domain behavior is an important subject, particularly applications related to earthing/grounding systems, from dc up into MHz range. In this paper, a numerical evaluation frequency-dependent complex impedance hemispherical ground electrode implemented. A closed-form solution for non-zero frequencies still difficult task achieve as evidenced previous paper dedicated subject and, therefore, approaches...

This paper is a contribution to the analysis of magnetic field mitigation shielding underground power cables. A hybrid finite-element method (FEM)/semi-analytical expansion adopted for numerical treatment open boundary problem. Different constitutive materials are studied, and comparison established between conductive (aluminum) ferromagnetic (steel) cases. horizontal flat configuration cable considered. It concluded that aluminum more efficient as far concerned.

This paper is a contribution to the evaluation of electromagnetic fields due underground power cables. Open boundary 2-D problems may be treated combining finite element method (FEM) inside region surrounded by regular (cylindrical) fictitious surface with semi-analytical (BEM) describe field outside this region. For region, generalization Pollaczek's solution applied, taking into account eddy currents in soil and proximity effect between soil/air plane cylinder radius. The validated using...

This article is the authors’ last contribution to a trilogy of research papers submitted Energies’ Special Issue on Electromagnetic Field Computation, aimed at theoretical analysis and numerical computation frequency-dependent complex impedance hemispherical electrodes. In this work, we consider pair distant identical electrodes buried in ground, whose constitutive parameters (conductivity permittivity) are assigned diverse values. Simulation experiments carried out using full-wave finite...

Coupled mode theory in dielectric waveguides has been studied for parallel and non-parallel waveguides, among bent straight optical between two non-concentric or even concentric ring waveguides. The last case is treated this work. Results are compared to those obtained by using the finite element method (FEM). We influence of curvature radius, separation distance refractive index inner waveguide energy transfer In particular, mechanism was analyzed.

A general solution for the magnetic field in soil is developed that satisfies arbitrary boundary conditions on an underground cylindrical surface at a finite depth below earth/air plane surface. quasi-steady state hypothesis assumed. The series impedance of cable with perfectly conducting sheath evaluated taking into account skin effect soil. numerical results are compared F. Pollaczek's (1926) classical solution.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML"...

In this paper, a magnetic field analysis is done for spherical shell-like induction machines with zenithal progressive traveling wave, using an analytical model in coordinates. These models have major importance the simulation, project, and preliminary optimization of devices due to its solutions physical insight. The made machine study electromagnetic mechanical quantities, as field, induced currents, torque. developed validated, first set generic windings distributions results commercial...

This paper deals with magnetic field mitigation techniques for underground power systems by using conductive or ferromagnetic shielding plates. Two new aspects are considered in this beside the effectiveness analysis: contribution to series impedance and losses due conducting set formed plate/earth return path. A finite thickness is assumed buried parallel soil/air plane surface order model induction of a cable system flat configuration. An analytical method, appropriate deal possible...

The design of magnetic cores can be carried out by taking into account the optimization different parameters in accordance with application requirements. Considering specifications fast field cycling nuclear resonance (FFC-NMR) technique, flux density distribution, at sample insertion volume, is one core that needs to evaluated. Recently, it has been shown FFC-NMR magnets built on basis solenoid coils ferromagnetic cores. Since this type apparatus requires high uniformity, a new magnet using...

The hemispherical ground electrode is a basic whose analysis appears in many textbooks on electromagnetics chapters dedicated to steady currents. Considering soil with given resistivity and an perimeter, the DC resistance simply calculated from ratio resistivity/perimeter. Strangely, generalization of this result AC regimes missing. issue frequency-domain impedance has been avoided literature despite its trivial geometry. But problem indeed not easy; electromagnetic field calculation...

Abstract Exposure to low frequency magnetic fields has been a matter of health concern and controversy over the past years. These aspects motivated development methods algorithms for field evaluation due power transmission lines cables. In this paper special attention is given buried Results different values permeability soil are obtained, presented compared with standard approximation. confirm importance method developed in paper, not only as reference but also mandatory higher frequency....

In this paper special attention is given to the mitigation of magnetic field originated by underground power transmission cables. The system analyzed composed a set nm conductors, parallel cables, forming grid. An optimization algorithm was developed in order obtain best location install grid conductors. reduce number unknowns, taking into account symmetry system. Results are presented showing influence conductors and its cross-section dimensions on performance. Copyright © 2010 John Wiley &...

A new hybrid finite element method (HFEM) was developed, using basis functions of first and second order, to analyse the electromagnetic wave propagation in three types waveguides: disk waveguides, ring waveguides cylindrical waveguides. For validation purposes, results obtained with HFEM were compared those a recursive (RFEM) two different analytical methods. The domain discretization effect on examined either uniform distribution nodes or Delaunay method. show that method, used mesh...

A general solution for the magnetic field in soil is developed that satisfies arbitrary conditions on a set of underground cylindrical surfaces at finite depth below earth/air surface. The takes into account singularities all orders located axis each circular boundary, allowing boundary plane to be satisfied and imposing regularity infinity. method used evaluate series-impedance matrix system comprising three cables flat configuration. Numerical results are presented contribution Earth...

This paper is a contribution to the evaluation of losses in ferromagnetic media, due eddy currents and magnetic hysteresis, field source being time harmonic induced e.m.f. The fundamental equations are solved numerically by using finite element formulation, corresponding space discretization, second order trapezoidal (Crank-Nickolson) method for integration. applied soft sample, hysteresis simulated classical Preisach model.

This paper is a contribution to the electromagnetic field evaluation of open boundary time-harmonic eddy current problems, using hybrid Finite Element/Boundary Fourier Transform method (FE/BFT). The finite element applies inside fictitious cylindrical surface where conductors lie and whole empty space outside cylinder. descriptions, outside, are matched on set discretization nodes over boundary. handled in spatial frequency domain by use suitable discrete transform.

This paper is a contribution to the open boundary axisymmetric quasi-static magnetic field problems in presence of eddy currents. A hybrid method developed combining finite-element inside an inner region with special boundary-element for outer based on analytical treatment. Spherical coordinates become appropriate due consideration spherical surfaces separating and regions.

In this article, we evaluate the practical limits of length segmentation tower-footing grounding modeling. The objective is to present a relation between computational efficiency and for transmission lines lightning performance studies. A physically consistent electromagnetic model based on field theory applied. process designed improve efficiency, in proposals suggested literature, maintain precision results. criteria considered acceptable given (in reference) are as follows: 1) potential...