Home Modelling axial vibration in windings of power transformers
Article Open Access

Modelling axial vibration in windings of power transformers

  • Pawel Witczak EMAIL logo and Michal Swiatkowski
Published/Copyright: December 29, 2017

Abstract

This paper describes the method of homogenization of material properties applied to windings used in power transformers. Exemplary results of natural modes of vibrations obtained by means of finite elements method are also included.

1 Introduction

The windings in power transformers have a complex and composite structure which is mechanically highly anisotropic and relatively weak, especially in high voltage units where the amount of insulation material is substantial. The presence of insulation, whose rigidity is about two hundred times less than for copper, is most important when deformations in axial direction are considered. The proper estimation of these phenomena is important for the analysis of the winding resistance against operational short-circuit [1] and also for the winding vibration at load [2, 3, 4, 5, 6]. In either case arises the question of introducing an equivalent material for the winding area because the exact representation of complex geometry and material heterogeneity would require unacceptable computational effort. The significance of winding vibration in power transformers is clearly visible for units with powers of 100 MVA or greater for which the load noise dominates that of magnetostriction origin.

2 Winding structure in power transformers

The typical structure of low and high voltage windings in large power transformers consists of a series of coils axially separated by a set of spacers uniformly distributed along the winding circumference and forming the radial cooling ducts filled with oil. The coils are usually wired with continuously transposed cable (CTC).The above system includes a set of repetitive portions with the same geometry, material structure and electromagnetic excitation. Each portion consists of sectors of a single coil accompanied with four quarters of spacers. The outlook of a sector together with a cross-section of CTC is displayed in Figure 1. The distribution of mechanical and electromagnetic stress acting on this elementary section is quite complex and it depends on the section’s position in the winding. The all further analysis will concern the excitations and constraints in the axial direction only.

Figure 1 Outlook of elementary sector of winding and CTC cross-section
Figure 1

Outlook of elementary sector of winding and CTC cross-section

3 Principle of homogenization

The aim of this investigation is to find the equivalent properties of a homogeneous material having the same outer dimensions (d0,α0,h0) as the sector in Figure 1 and simultaneously, reacting in the same way under external excitation. The equation governing this analysis is the virtual work principle

S(V)σijnjuidS=V(S)σijϵijdV(1)

where σij, εij are stress and strain and ui is a virtual displacement. The condition of static equilibrium requires the null value of displacement along the part of outer boundary. If the homogenous volume, having a constant cross-section Sh normal to 0z axis, is subjected to the unidirectional load created by axial displacement of the boundary surface uz0 the equation (1) converts into

phShuz0=Ezuzz2Shh0(2)

where ph denotes the pressure on the displaced surface. The strain varies linearly in this case and therefore, we obtain Hooke’s law

ph=Ezuz0h0(3)

In other words, the homogenization of some volume of interest means that having the same displacement and elastic energy we can approximate the integral equation

Fi=Kui(4)

introducing the artificial stiffness K linking the components of force Fi and displacement ui which are mean quantities for the given volume.

4 Numerical model of winding sector

The transformer windings are significantly pre-stressed in the axial direction. It means that CTC filaments in the area directly under spacers may be assumed to be tightly connected by the friction forces, but outside they can move more or less independently. To designate the equivalent Young modulus in the axial direction a numerical model consisting of two CTC filaments, together with four quarters of a spacer, was developed. Its outlook is shown in Figure 2.

Figure 2 Numerical model of CTC section
Figure 2

Numerical model of CTC section

The model is subjected to virtual, axial symmetric displacements uzm (the same as in the homogenous case) and constrained in the circumferential direction. Results of the calculations are presented in Figure 3.

Figure 3 Strain and stress fields inside CTC section (white is null value)
Figure 3

Strain and stress fields inside CTC section (white is null value)

Observing fields shown in Figure 3 we see that the energy of the deformations σzzεzz is stored in the spacers only, besides, in a uniform manner. It is worth noting that shear stresses are almost absent on the outer surface of the model. The choice of the equivalent homogenous material is made assuming the same axial outer displacement and total energy stored as in a real case. The above remarks lead to the following equation resulting from (1) and (2)

Esuz0hs2Vs=Ezuz0h02Vh(5)

where Vs and hs are the volume and height of the spacer and Vh and h0 refer to the homogenous material. After simple manipulations we get an expression describing the relation between the values of axial Young modulus Ez of the equivalent homogenous structure and of the spacer’s material Es

Ez=Esh0h0hzα0α1α0(6)

Geometric dimensions are presented in Figure 1. Inserting their values for 120 MVA units we have for HV and LV windings produce the following results: EzHV = 1.47 Es and EzLV = 1.58 Es.

Quite often CTC are hardened by their epoxy filler during the drying process of transformer windings. In such a case we cannot assume that CTC filaments directly contact themselves and we must take into account the amount of relatively soft resin in between. A finite elements model showing the sector of an exemplary CTC is presented in Figure 4. The number of filaments inside is even not odd in order to simplify the analytic expressions. Bearing in mind that the radius of transformer coils is much larger than their thickness, the Cartesian system is used but preserving the notation of axes like in cylindrical coordinates.

Figure 4 Numerical model of CTC
Figure 4

Numerical model of CTC

The virtual displacement was applied along the 0r axis for points belonging to external planes normal to that direction. The remaining outer boundary was left free, creating the one-dimensional load case. Distributions of dominating strain and stress components are presented in Figure 5. The strain has a non-zero value in the areas of epoxy filler only, therefore, the elastic energy is just stored there as well. Observing the profile of displacement ur shown in Figure 6 along axis nr presented in Figure 4, we may conclude that each layer of resin contains almost the same amount of elastic energy.

Figure 5 Strain and stress fields inside CTC cross-section (white is null value)
Figure 5

Strain and stress fields inside CTC cross-section (white is null value)

Figure 6 Radial displacement field inside CTC cross-section
Figure 6

Radial displacement field inside CTC cross-section

The outer dimensions of the CTC cross-section are hr, hz and hα (see Figure 4) and the relative volumes of filler along axes nr and nz are gr and gz. Denoting the virtual displacement value by u0 and Young modulus of filler by Ef we may compute the elastic energy stored in the CTC from

W=Efu02grhr2VCTCa(7)

where VaCTC denotes the active volume of the filler

VCTCa=grhrhα1gzhz(8)

The same amount of energy stored in the homogenized equivalent material under the same virtual displacement in the radial direction is given by

W=Eeru02hr2hrhαhz(9)

what immediately results with the value of equivalent material property in the radial direction is

Eer=Ef1gzgr(10)

The property of CTC in the axial direction is obtained by the simple exchange of subscripts

Eez=Ef1grgz(11)

When the winding has radial cooling ducts we must repeat the analysis of axial deformation described earlier but now with two areas having different elastic properties: Es for spacer and Eez for CTC. Applying the one-dimensional virtual displacement u0 to the outer surfaces of the spacers we must find the unknown displacement u1 on the boundary between spacer and CTC. It results from stress equilibrium

σzz=Esu0u1hs=Eezu1hz(12)

where hs is spacer thickness.

Figure 7 Cross-section of two-body winding sector
Figure 7

Cross-section of two-body winding sector

Elastic energy stored now has two components W1 for spacer, W2 for CTC and it is calculated from

W1=Esu0u1hs2hrhsα0α1W2=Eezu1hz2hrhzα0α1(13)

The sum of W1 and W2 must be equal to energy in the homogenous material W having larger axial and circumferential size

W=Eeqzu0hz+hs2hrhz+hsα0(14)

The equivalent material property in the axial direction of the winding sector containing the CTC turns and spacer is noted here by Eeqz. Equating (12) and (13) and making some simple manipulations we get the final expression

Eeqz=11gsEez+gsEsα0α1α0(15)

where gs is the relative size of the spacer

gs=hshs+hz(16)

Equation (14) is an extension of (6) for two elastic materials subjected to the same stress. It is necessary to remember that amount of insulation material inside CTC depends heavily on its type and its stiffness has a non-linear shape against the pre-stress value. The remaining moduli of an orthotropic material, namely Eeqr and Eeqα are calculated in an analogous way. It should be underlined that material having orthotropic properties needs to also specify three shear moduli and three Poisson factors. The shear moduli are obtained by similarly applying the virtual displacement but now in tangent direction. The Poisson factors are calculated from their definition as the ratio of strain along two perpendicular axes.

5 Exemplary results

The winding area in a 120 MVA transformer was modelled using solid and shell elements having orthotropic properties, where windings with axial wedges were constructed within cylindrical coordinates but support plates were modelled under theCartesian system. All materials used in the winding zone have a significant anisotropy. For example, the equivalent material in a HV winding has the following properties along cylindrical coordinates: (Er, Eα, Ez) = (3.2, 67.8, 0.54) GPa and the pressboard is represented in Cartesian system by (Ex, Ey, Ez) = (9.1, 6.8, 0.5) GPa.

Figure 8 Finite elements model of of phase windings in 120 MVA transformer (1/8 volume shown)
Figure 8

Finite elements model of of phase windings in 120 MVA transformer (1/8 volume shown)

The natural mode of vibration having the lowest frequency with dominating axial displacements is presented in Figure 9. It was obtained assuming the core and steel supports to be infinitely stiff.

Figure 9 Shape of natural mode of vibration of winding zone, f = 204 Hz (color map shows axial displacement)
Figure 9

Shape of natural mode of vibration of winding zone, f = 204 Hz (color map shows axial displacement)

Besides the axial deformation strongly coupled in space with the axial forces present in winding we also see the elliptic deformation varying along the winding height which in turn corresponds to the circumferential non-uniformity of radial forces.

6 Conclusions

The analysis presented above clearly indicates the necessity of representation of transformer windings for vibration investigations by anisotropic materials. The main difficulty here is to get the proper values of these parameters which depend on pre-stress of the winding zone and also on distribution of insulation inside the CTC area. The careful measurements of particular properties of elements of winding structure connected with a mathematical model of the winding are essential for the accuracy of the final results.

References

[1] Minhas M.S.A., Dynamic Behaviour of Transformer Winding under Short-Circuits, PhD thesis, 2007, Johannesburg Univ.Search in Google Scholar

[2] Wang Y., Pan J., Jin M., Finite Element Modelling of the Vibration of a Power Transformer, Proceedings of Acoustics, 2011, paper 34, Gold CoastSearch in Google Scholar

[3] Majer K., Analysis of Vibration and Noise in Converter Transformers, Lodz University of Technology, 2013, ZN 1178, (in Polish)Search in Google Scholar

[4] Ertl M., Landes H., Investigation of load noise generation of large power transformer by means of coupled 3D FEM analysis, COMPEL, 2007, 26, 3, 788-799.10.1108/03321640710751226Search in Google Scholar

[5] Reyne G., Magnin H., Berliat G., Clerc C., A Supervisor for the Successive 3D Computations of Magnetic, Mechanical and Acoustic Quantities in Power Oil Inductors and Transformers, in Magnetics, IEEE Transactions on, 1994, 30, 5, 3292-3295.10.1109/20.312641Search in Google Scholar

[6] Rausch M., Kaltenbacher M., Landes H., Lerch R., Combination of Finite and Boundary Element Methods in Investigation and Prediction of Load-Controlled Noise of Power Transformers, Journal of Sound and Vibration, 2002, 250, 2, 323-338.10.1006/jsvi.2001.3934Search in Google Scholar

Received: 2017-11-3
Accepted: 2017-11-12
Published Online: 2017-12-29

© 2017 Pawel Witczak and Michal Swiatkowski

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Articles in the same Issue

  1. Regular Articles
  2. Analysis of a New Fractional Model for Damped Bergers’ Equation
  3. Regular Articles
  4. Optimal homotopy perturbation method for nonlinear differential equations governing MHD Jeffery-Hamel flow with heat transfer problem
  5. Regular Articles
  6. Semi- analytic numerical method for solution of time-space fractional heat and wave type equations with variable coefficients
  7. Regular Articles
  8. Investigation of a curve using Frenet frame in the lightlike cone
  9. Regular Articles
  10. Construction of complex networks from time series based on the cross correlation interval
  11. Regular Articles
  12. Nonlinear Schrödinger approach to European option pricing
  13. Regular Articles
  14. A modified cubic B-spline differential quadrature method for three-dimensional non-linear diffusion equations
  15. Regular Articles
  16. A new miniaturized negative-index meta-atom for tri-band applications
  17. Regular Articles
  18. Seismic stability of the survey areas of potential sites for the deep geological repository of the spent nuclear fuel
  19. Regular Articles
  20. Distributed containment control of heterogeneous fractional-order multi-agent systems with communication delays
  21. Regular Articles
  22. Sensitivity analysis and economic optimization studies of inverted five-spot gas cycling in gas condensate reservoir
  23. Regular Articles
  24. Quantum mechanics with geometric constraints of Friedmann type
  25. Regular Articles
  26. Modeling and Simulation for an 8 kW Three-Phase Grid-Connected Photo-Voltaic Power System
  27. Regular Articles
  28. Application of the optimal homotopy asymptotic method to nonlinear Bingham fluid dampers
  29. Regular Articles
  30. Analysis of Drude model using fractional derivatives without singular kernels
  31. Regular Articles
  32. An unsteady MHD Maxwell nanofluid flow with convective boundary conditions using spectral local linearization method
  33. Regular Articles
  34. New analytical solutions for conformable fractional PDEs arising in mathematical physics by exp-function method
  35. Regular Articles
  36. Quantum mechanical calculation of electron spin
  37. Regular Articles
  38. CO2 capture by polymeric membranes composed of hyper-branched polymers with dense poly(oxyethylene) comb and poly(amidoamine)
  39. Regular Articles
  40. Chain on a cone
  41. Regular Articles
  42. Multi-task feature learning by using trace norm regularization
  43. Regular Articles
  44. Superluminal tunneling of a relativistic half-integer spin particle through a potential barrier
  45. Regular Articles
  46. Neutrosophic triplet normed space
  47. Regular Articles
  48. Lie algebraic discussion for affinity based information diffusion in social networks
  49. Regular Articles
  50. Radiation dose and cancer risk estimates in helical CT for pulmonary tuberculosis infections
  51. Regular Articles
  52. A comparison study of steady-state vibrations with single fractional-order and distributed-order derivatives
  53. Regular Articles
  54. Some new remarks on MHD Jeffery-Hamel fluid flow problem
  55. Regular Articles
  56. Numerical investigation of magnetohydrodynamic slip flow of power-law nanofluid with temperature dependent viscosity and thermal conductivity over a permeable surface
  57. Regular Articles
  58. Charge conservation in a gravitational field in the scalar ether theory
  59. Regular Articles
  60. Measurement problem and local hidden variables with entangled photons
  61. Regular Articles
  62. Compression of hyper-spectral images using an accelerated nonnegative tensor decomposition
  63. Regular Articles
  64. Fabrication and application of coaxial polyvinyl alcohol/chitosan nanofiber membranes
  65. Regular Articles
  66. Calculating degree-based topological indices of dominating David derived networks
  67. Regular Articles
  68. The structure and conductivity of polyelectrolyte based on MEH-PPV and potassium iodide (KI) for dye-sensitized solar cells
  69. Regular Articles
  70. Chiral symmetry restoration and the critical end point in QCD
  71. Regular Articles
  72. Numerical solution for fractional Bratu’s initial value problem
  73. Regular Articles
  74. Structure and optical properties of TiO2 thin films deposited by ALD method
  75. Regular Articles
  76. Quadruple multi-wavelength conversion for access network scalability based on cross-phase modulation in an SOA-MZI
  77. Regular Articles
  78. Application of ANNs approach for wave-like and heat-like equations
  79. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  80. Study on node importance evaluation of the high-speed passenger traffic complex network based on the Structural Hole Theory
  81. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  82. A mathematical/physics model to measure the role of information and communication technology in some economies: the Chinese case
  83. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  84. Numerical modeling of the thermoelectric cooler with a complementary equation for heat circulation in air gaps
  85. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  86. On the libration collinear points in the restricted three – body problem
  87. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  88. Research on Critical Nodes Algorithm in Social Complex Networks
  89. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  90. A simulation based research on chance constrained programming in robust facility location problem
  91. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  92. A mathematical/physics carbon emission reduction strategy for building supply chain network based on carbon tax policy
  93. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  94. Mathematical analysis of the impact mechanism of information platform on agro-product supply chain and agro-product competitiveness
  95. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  96. A real negative selection algorithm with evolutionary preference for anomaly detection
  97. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  98. A privacy-preserving parallel and homomorphic encryption scheme
  99. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  100. Random walk-based similarity measure method for patterns in complex object
  101. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  102. A Mathematical Study of Accessibility and Cohesion Degree in a High-Speed Rail Station Connected to an Urban Bus Transport Network
  103. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  104. Design and Simulation of the Integrated Navigation System based on Extended Kalman Filter
  105. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  106. Oil exploration oriented multi-sensor image fusion algorithm
  107. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  108. Analysis of Product Distribution Strategy in Digital Publishing Industry Based on Game-Theory
  109. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  110. Expanded Study on the accumulation effect of tourism under the constraint of structure
  111. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  112. Unstructured P2P Network Load Balance Strategy Based on Multilevel Partitioning of Hypergraph
  113. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  114. Research on the method of information system risk state estimation based on clustering particle filter
  115. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  116. Demand forecasting and information platform in tourism
  117. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  118. Physical-chemical properties studying of molecular structures via topological index calculating
  119. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  120. Local kernel nonparametric discriminant analysis for adaptive extraction of complex structures
  121. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  122. City traffic flow breakdown prediction based on fuzzy rough set
  123. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  124. Conservation laws for a strongly damped wave equation
  125. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  126. Blending type approximation by Stancu-Kantorovich operators based on Pólya-Eggenberger distribution
  127. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  128. Computing the Ediz eccentric connectivity index of discrete dynamic structures
  129. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  130. A discrete epidemic model for bovine Babesiosis disease and tick populations
  131. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  132. Study on maintaining formations during satellite formation flying based on SDRE and LQR
  133. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  134. Relationship between solitary pulmonary nodule lung cancer and CT image features based on gradual clustering
  135. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  136. A novel fast target tracking method for UAV aerial image
  137. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  138. Fuzzy comprehensive evaluation model of interuniversity collaborative learning based on network
  139. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  140. Conservation laws, classical symmetries and exact solutions of the generalized KdV-Burgers-Kuramoto equation
  141. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  142. After notes on self-similarity exponent for fractal structures
  143. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  144. Excitation probability and effective temperature in the stationary regime of conductivity for Coulomb Glasses
  145. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  146. Comparisons of feature extraction algorithm based on unmanned aerial vehicle image
  147. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  148. Research on identification method of heavy vehicle rollover based on hidden Markov model
  149. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  150. Classifying BCI signals from novice users with extreme learning machine
  151. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  152. Topics on data transmission problem in software definition network
  153. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  154. Statistical inferences with jointly type-II censored samples from two Pareto distributions
  155. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  156. Estimation for coefficient of variation of an extension of the exponential distribution under type-II censoring scheme
  157. Special issue on Nonlinear Dynamics in General and Dynamical Systems in particular
  158. Analysis on trust influencing factors and trust model from multiple perspectives of online Auction
  159. Special Issue on Advances on Modelling of Flowing and Transport in Porous Media
  160. Coupling of two-phase flow in fractured-vuggy reservoir with filling medium
  161. Special Issue on Advances on Modelling of Flowing and Transport in Porous Media
  162. Production decline type curves analysis of a finite conductivity fractured well in coalbed methane reservoirs
  163. Special Issue on Advances on Modelling of Flowing and Transport in Porous Media
  164. Flow Characteristic and Heat Transfer for Non-Newtonian Nanofluid in Rectangular Microchannels with Teardrop Dimples/Protrusions
  165. Special Issue on Advances on Modelling of Flowing and Transport in Porous Media
  166. The size prediction of potential inclusions embedded in the sub-surface of fused silica by damage morphology
  167. Special Issue on Advances on Modelling of Flowing and Transport in Porous Media
  168. Research on carbonate reservoir interwell connectivity based on a modified diffusivity filter model
  169. Special Issue on Advances on Modelling of Flowing and Transport in Porous Media
  170. The method of the spatial locating of macroscopic throats based-on the inversion of dynamic interwell connectivity
  171. Special Issue on Advances on Modelling of Flowing and Transport in Porous Media
  172. Unsteady mixed convection flow through a permeable stretching flat surface with partial slip effects through MHD nanofluid using spectral relaxation method
  173. Special Issue on Advances on Modelling of Flowing and Transport in Porous Media
  174. A volumetric ablation model of EPDM considering complex physicochemical process in porous structure of char layer
  175. Special Issue on Advances on Modelling of Flowing and Transport in Porous Media
  176. Numerical simulation on ferrofluid flow in fractured porous media based on discrete-fracture model
  177. Special Issue on Advances on Modelling of Flowing and Transport in Porous Media
  178. Macroscopic lattice Boltzmann model for heat and moisture transfer process with phase transformation in unsaturated porous media during freezing process
  179. Special Issue on Advances on Modelling of Flowing and Transport in Porous Media
  180. Modelling of intermittent microwave convective drying: parameter sensitivity
  181. Special Issue on Advances on Modelling of Flowing and Transport in Porous Media
  182. Simulating gas-water relative permeabilities for nanoscale porous media with interfacial effects
  183. Special Issue on Advances on Modelling of Flowing and Transport in Porous Media
  184. Simulation of counter-current imbibition in water-wet fractured reservoirs based on discrete-fracture model
  185. Special Issue on Advances on Modelling of Flowing and Transport in Porous Media
  186. Investigation effect of wettability and heterogeneity in water flooding and on microscopic residual oil distribution in tight sandstone cores with NMR technique
  187. Special Issue on Advances on Modelling of Flowing and Transport in Porous Media
  188. Analytical modeling of coupled flow and geomechanics for vertical fractured well in tight gas reservoirs
  189. Special Issue on Ever-New "Loopholes" in Bell’s Argument and Experimental Tests
  190. Special Issue: Ever New "Loopholes" in Bell’s Argument and Experimental Tests
  191. Special Issue on Ever-New "Loopholes" in Bell’s Argument and Experimental Tests
  192. The ultimate loophole in Bell’s theorem: The inequality is identically satisfied by data sets composed of ±1′s assuming merely that they exist
  193. Special Issue on Ever-New "Loopholes" in Bell’s Argument and Experimental Tests
  194. Erratum to: The ultimate loophole in Bell’s theorem: The inequality is identically satisfied by data sets composed of ±1′s assuming merely that they exist
  195. Special Issue on Ever-New "Loopholes" in Bell’s Argument and Experimental Tests
  196. Rhetoric, logic, and experiment in the quantum nonlocality debate
  197. Special Issue on Ever-New "Loopholes" in Bell’s Argument and Experimental Tests
  198. What If Quantum Theory Violates All Mathematics?
  199. Special Issue on Ever-New "Loopholes" in Bell’s Argument and Experimental Tests
  200. Relativity, anomalies and objectivity loophole in recent tests of local realism
  201. Special Issue on Ever-New "Loopholes" in Bell’s Argument and Experimental Tests
  202. The photon identification loophole in EPRB experiments: computer models with single-wing selection
  203. Special Issue on Ever-New "Loopholes" in Bell’s Argument and Experimental Tests
  204. Bohr against Bell: complementarity versus nonlocality
  205. Special Issue on Ever-New "Loopholes" in Bell’s Argument and Experimental Tests
  206. Is Einsteinian no-signalling violated in Bell tests?
  207. Special Issue on Ever-New "Loopholes" in Bell’s Argument and Experimental Tests
  208. Bell’s “Theorem”: loopholes vs. conceptual flaws
  209. Special Issue on Ever-New "Loopholes" in Bell’s Argument and Experimental Tests
  210. Nonrecurrence and Bell-like inequalities
  211. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  212. Three-dimensional computer models of electrospinning systems
  213. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  214. Electric field computation and measurements in the electroporation of inhomogeneous samples
  215. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  216. Modelling of magnetostriction of transformer magnetic core for vibration analysis
  217. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  218. Comparison of the fractional power motor with cores made of various magnetic materials
  219. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  220. Dynamics of the line-start reluctance motor with rotor made of SMC material
  221. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  222. Inhomogeneous dielectrics: conformal mapping and finite-element models
  223. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  224. Topology optimization of induction heating model using sequential linear programming based on move limit with adaptive relaxation
  225. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  226. Detection of inter-turn short-circuit at start-up of induction machine based on torque analysis
  227. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  228. Current superimposition variable flux reluctance motor with 8 salient poles
  229. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  230. Modelling axial vibration in windings of power transformers
  231. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  232. Field analysis & eddy current losses calculation in five-phase tubular actuator
  233. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  234. Hybrid excited claw pole generator with skewed and non-skewed permanent magnets
  235. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  236. Electromagnetic phenomena analysis in brushless DC motor with speed control using PWM method
  237. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  238. Field-circuit analysis and measurements of a single-phase self-excited induction generator
  239. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  240. A comparative analysis between classical and modified approach of description of the electrical machine windings by means of T0 method
  241. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  242. Field-based optimal-design of an electric motor: a new sensitivity formulation
  243. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  244. Application of the parametric proper generalized decomposition to the frequency-dependent calculation of the impedance of an AC line with rectangular conductors
  245. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  246. Virtual reality as a new trend in mechanical and electrical engineering education
  247. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  248. Holonomicity analysis of electromechanical systems
  249. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  250. An accurate reactive power control study in virtual flux droop control
  251. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  252. Localized probability of improvement for kriging based multi-objective optimization
  253. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  254. Research of influence of open-winding faults on properties of brushless permanent magnets motor
  255. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  256. Optimal design of the rotor geometry of line-start permanent magnet synchronous motor using the bat algorithm
  257. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  258. Model of depositing layer on cylindrical surface produced by induction-assisted laser cladding process
  259. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  260. Detection of inter-turn faults in transformer winding using the capacitor discharge method
  261. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  262. A novel hybrid genetic algorithm for optimal design of IPM machines for electric vehicle
  263. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  264. Lamination effects on a 3D model of the magnetic core of power transformers
  265. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  266. Detection of vertical disparity in three-dimensional visualizations
  267. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  268. Calculations of magnetic field in dynamo sheets taking into account their texture
  269. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  270. 3-dimensional computer model of electrospinning multicapillary unit used for electrostatic field analysis
  271. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  272. Optimization of wearable microwave antenna with simplified electromagnetic model of the human body
  273. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  274. Induction heating process of ferromagnetic filled carbon nanotubes based on 3-D model
  275. Special Issue: The 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering ISEF 2017
  276. Speed control of an induction motor by 6-switched 3-level inverter
Downloaded on 10.9.2025 from https://www.degruyterbrill.com/document/doi/10.1515/phys-2017-0103/html
Scroll to top button