Electrodynamic Forces Research Articles

Analysis and verification of electrodynamic force, thermal stress and current sharing for CRAFT converter structure design

In the design realm of fusion power supplies, structural components play a pivotal role in ensuring the safety of fusion devices. To verify the reliability of the converter structure design at the Comprehensive Research Facility for Fusion Technology (CRAFT), meticulous analysis of the converter's dynamic impact is carefully performed based on the worst fault current (400 kA), firstly. Subsequently, the thermal stress analysis based on the maximum allowable steady-state temperature is finished, and the equivalent thermal stress, thermal deformation, maximum shear stress of a single bridge arm and the whole converter are studied. Furthermore, a simple research method involving the current-sharing characteristics of a bridge arm with multi-thyristor parallel connection is proposed using a combination of Simplorer with Q3D in ANSYS. The results show that the current-sharing characteristics are excellent. Finally, the structural design has been meticulously tailored to meet the established requirements.

Simulation Analysis and Experimental Research on Vibration Characteristics of Series Reactors in Multiple Operating Status

Abstract This article examines the vibration properties of reactors across various operational scenarios, including normal operation, interturn arc short circuit faults, and interturn metal fusion short circuit faults. It begins by analyzing the vibration mechanism of reactors, drawing upon principles of electromagnetic induction and Ampere’s law. Then, a multi condition mechanical-electromagnetic interaction model was established for the series reactor, and the axial electrodynamic force distribution of the reactor was analyzed. Finally, a vibration characteristics test platform for series reactors under multiple operating conditions was built, and the vibration velocity distribution of the reactors was analyzed. The research results indicate that under normal operating condition, the maximum vibration velocity of the reactor appears at its lower end; When the Interturn arc short circuit fault occurs, the vibration speed at different positions of the reactor increases, and the vibration velocity at the short-circuit point will significantly increase with the development of the short-circuit fault; When the interturn metal fusion short circuit fault occurs, the amplitude of the vibration signal at the short-circuit point is greater than that of the arc short-circuit vibration signal.

Multiphysics simulation of two-phase viscous fluid flow steered by electric field for jetting of microdroplets

In this research, we delve into the intricacies of viscous fluid flow with electric field coupling by employing the Finite Element Method (FEM) in tandem with the level set method. We generate a weak form for satisfying governing equations for electric field and fluid velocity while two phases are tracked by the level set function. The primary focus of this study is the complex interactions between free-falling jet and electric field, and the behavior of droplet encompassing deformation, fission, and fusion under the influence of electric field. The main contribution of this paper is given a new implement by using the P1/P1 scheme to directly solve the weak forms of coupled governing equations, which significantly improves calculation efficiency compared to the P2/P1 scheme, and we open source the code. This implement is verified by comparing with the experimental results of oil droplets deforming under an electric field. Computations are performed by FEniCS open-source packages. The phenomena documented underscore the multifaceted relationship between electrodynamic forces and fluid mechanics, accentuated distinctly under non-uniform electric field conditions.

Electrodynamic Forces in Main Three-Phase Busbar System of Low-Voltage Switchgear—FEA Simulation

This paper concerns the effects of electrodynamic forces that act on current paths that are part of high-grade industrial distribution switchgear. This work is composed of experimental and simulation sections. In the experimental section, the short-circuit tests are presented and the occurrence of electrodynamic forces are shown in a visible way. The formation of electrodynamic forces in the current circuits of electrical energy distribution systems is related to the flow of high currents, but mostly it is related to short-circuit currents. In order to highlight these phenomena, the detailed specification of the parameters during tests is displayed. In the simulation section, the physical phenomenon of electrodynamic forces is being captured by employing a detailed real-scale model of switchgear and current paths. Therefore, the authors proposed employment of the FEM (finite element method) in order to obtain values of electrodynamic forces acting on the current paths by executing the detailed 3D coupled simulation. The analysis of the results and aftermath effects of their interactions provided interesting conclusions that concerned the operation of such power distribution layouts in critical short-circuit conditions.

Dalton's law of partial optical thermodynamic pressures in highly multimoded nonlinear photonic systems.

We show that in highly multimoded nonlinear photonic systems, the optical thermodynamic pressures emerging from different species of the optical field obey Dalton's law of partial pressures. In multimode settings, the optical thermodynamic pressure is defined as the conjugate to the extensive variable associated with the system's total number of modes and is directly related to the actual electrodynamic radiation forces exerted at the physical boundaries of the system. Here, we extend this notion to photonic configuration supporting different species of the optical field. Under thermal equilibrium conditions, we formally derive an equation that establishes a direct link between the partial thermodynamic pressures and the electrodynamic radiation pressures exerted by each polarization species. Our theoretical framework provides a straightforward approach for quantifying the total radiation pressures through the system's thermodynamic variables without invoking the Maxwell stress tensor formalism. In essence, we show that the total electrodynamic pressure in such arrangements can be obtained in an effortless manner from initial excitation conditions, thus avoiding time-consuming simulations of the utterly complex multimode dynamics. To illustrate the validity of our results, we carry out numerical simulations in multimoded nonlinear optical structures supporting two polarization species and demonstrate excellent agreement with the Maxwell stress tensor method.

Fault diagnosis and analysis of a 110 kV transformer

This paper aims to provide valuable insights and assistance for ensuring the safe operation of a 110 kV main transformer by conducting an in-depth analysis of tap changer breather oil leakage defects. By employing transformer testing, disassembly analysis, and other methods, this study successfully identifies and prevents the possibility of transformer failure. The analysis reveals that the deformation of the transformer winding is caused by insufficient short-circuit resistance, which leads to the deformation of the medium-voltage windings under the continuous action of electrodynamic forces during near-area short-circuit currents. Near-area short-circuits are a significant contributing factor to transformer failures. Therefore, it is recommended to enhance operation and maintenance management for older main transformers and optimize protection settings to reduce the risk of near-area short-circuit failures, thus ensuring the safe and stable operation of the main transformer.

A NON-DESTRUCTIVE METHOD FOR EVALUATING THE ADHESION BETWEEN THE LAYERS OF METAL-POLYMER-METAL COMPOSITE MATERIALS

Development of a non-destructive measuring technique for evaluating the bonding quality of metal-polymer-metal composite sheet materials is introduced. Sufficient adhesion is necessary to ensure further shaping steps or bearing loads when used without failure due to delamination. Much attention is paid to determining the quality of gluing. According to the patent-literature review, no non-destructive measuring or quality control of layers’ bonding quality over the entire surface has been found. Thus, a new technical solution is proposed for defining the quality of bonding between the layers by means of electrodynamic repulsion forces arising from the pulse current passing over the metal layers of a composite in the counter direction. The feasibility of the method is tested in laboratory conditions. For its implementation, the necessary values of the test parameters are obtained, i.e., the values of the current transmitted through metal layers. In addition, the possibility of detecting local defects of different shapes and sizes with the proposed method is estimated.

Comparative analysis of the characteristics of outlet short circuit and winding insulation fault of distribution transformer and its preventive measures

AbstractOutlet short circuit on the low‐voltage (LV) side and winding inter‐turn short circuit faults are hazardous to transformer operation. To investigate the formation mechanism of winding insulation faults of distribution transformer, ANSYS Maxwell was used to build a coupled magnetic field‐circuit model with the same structural dimension as the actual distribution transformer. An outlet short circuit and winding inter‐turn insulation faults were set by using the voltage‐controlled switch in the external circuit of the model. Subsequently, the differences in the electromagnetic characteristics and the electrodynamic force distributions of the windings under three operating conditions, namely, nominal load, three‐phase outlet short circuit on the LV side and inter‐turn insulation failure were studied, respectively. The results show that compared with the rated load, in the cases of outlet short circuit and inter‐turn insulation faults, the amplitude of winding current increases by 20 and 50 times, the magnetic field strength grows by 20 and 17 times, and the electrodynamic force rises by 400 and 230 times, respectively. Outlet short circuit fault is more likely to cause the winding instability and deformation, and inter‐turn short circuit fault can easily burn out winding insulation. Therefore, corresponding preventive measures were proposed.

Examination of Electrodynamic Forces in High Voltage Disconnector Related to the Short-Circuit Current Using the Digital Twin Technology

Examination of Electrodynamic Forces in High Voltage Disconnector Related to the Short-Circuit Current Using the Digital Twin Technology

Active vibration isolation by emulating the inerter through relative acceleration feedback

This study focuses on the realisation of a small-scale inerter by relative acceleration feedback and its use to isolate vibration. Two accelerometers attached to the two mechanical terminals of an electrodynamic force actuator are used to obtain the relative acceleration signal. This signal is then amplified by a constant gain and fed back to the two electrical terminals of the electrodynamic actuator as a voltage command. This sensor-actuator system is coupled to a two Degree-Of-Freedom (DOF) mechanical oscillator to study the feedback loop’s stability and the maximum achievable inertance effect. A fully coupled simulation model including the dynamics of the two inertial accelerometers and the electrodynamic actuator is developed. It is shown that, because of the active control system emulating an inerter, an antiresonance appears in the transfer admittance function of the two DOF mechanical system. Therefore, significant vibration isolation effect can be achieved in the narrow frequency band around the antiresonance. The antiresonance frequency is easily tuned by adjusting the feedback gain. The synthetized inertance is a complex frequency dependent function, which is predominantly real-valued in the frequency range between 5 and 1600 Hz. It is shown that it does not depend on the mechanical system properties, but only on the properties of the transducers used and the signal conditioning in the feedback loop. As a result, this frequency range can be adjusted according to a particular application.

On the Magnetic Charge of an Electron and the Generalized Electrodynamic Forces

In the late 90s of XX century the author proposed a concept describing an electric charge as a rotating mass. Such a description makes it possible to exclude the Coulomb quantity from the system SI and to describe all electrodynamic quantities in mechanical dimensions. According to the dimensionality, a magnetic charge is an electric charge divided by the speed of light. In the 10s of the 21st century, the authors of this article proposed a generalization of the traditional system of Maxwell’s equations in the context of a mechanical description of electromagnetic quantities. The generalized system has a solution for single charges. From these solutions, one can construct the energy and momentum of the interaction of two electrons. In this case, the electron is the unit of two principles: the electric and the magnetic. The gradient of the interaction energy gives the interaction force of the electric charges of the electrons, and the time derivative of the interaction momentum gives the interaction force of the magnetic charges of two electrons. A formal description of these forces completes the article.

Capillary and Electrodynamic Forces-Driven Separation Detection of Metal Ions Using a Disposable Microfluidic Sensor with a Composite Electrode.

A disposable microfluidic channel sensor printed on a plastic platform was developed to analyze heavy metal ions (HMIs) as a model target species. Precise separation and detection of multiple targets were established by symmetrically applying a small AC potential on the carbon channel walls to induce an electrodynamic force. The separation device was constructed by covering it with a plastic lid to achieve capillary action in the channel. The sample flow rate was regulated by the hydrophilicity of the lid plastic and electrodynamic convection by the AC field, which was characterized by the contact angle measurement and the additional electrodynamic force. The flow variables and their relevance to the capillary phenomena were demonstrated, and the analytical parameters were optimized. The working electrode was modified with poly(diamino terthiophene) anchored with nanosized graphene oxide (pDATT/GO) to enhance the detection performance. The experimental variables for separating and detecting the target species were optimized according to the AC frequency and amplitude, sample flow rate, electrolytes, pH, temperature, and applied potential for detection. The linear dynamic ranges were between 0.1 and 200.0 ppb, with detection limits of 0.04 ± 0.023, 0.29 ± 0.05, 0.07 ± 0.011, and 0.14 ± 0.06 ppb for Cu2+ Cd2+, Hg2+, and Pb2+, respectively. Finally, the reliability of the proposed method was evaluated through analysis of HMIs in real water samples. The results were matched to those obtained through parallel analysis using ICP-MS at a 95% confidence level.

Active Vibration Control of a Rotating Machine with Voltage-Driven Electrodynamic Actuators Between Machine Feet and Steel Frame Foundation Under Multiple Base Excitations

PurposeIn the paper, a theoretical analysis—based on a 2D multibody model—is presented regarding active vibration control of a rotating machine with voltage-driven electrodynamic actuators between machine feet and steel frame foundation under multiple base excitations.MethodsMathematical formulations are derived in the time domain and then transferred into the Laplace domain, where a state space formulation is used to describe the controlled vibration system. With this mathematical formulations, it is possible to analyze separately the two different kinds of actuator forces—the actuator forces, caused by the motion-induced voltage and the actuator forces caused by the control system—and their influence on the vibration behavior. Afterward, the mathematical formulations are transferred into the Fourier domain, for considering harmonic excitations of the base. Also a numerical example is presented, where different cases regarding machine mounting and operation conditions are investigated and compared to each other.ResultsIt could be clearly demonstrated that with the presented control system, most of the resonance peaks in the frequency responses could be strongly damped.ConclusionsWith the presented mathematical formulations, the controlled vibration system can be well described, considering separately the two different kinds of electrodynamic actuator forces and their influence.

Analysis of short-circuit electrodynamic vibration response of triangularly arranged iced transmission lines based on finite element method

The alternating reciprocating electrodynamic load with periodic variation of short-circuit current will be generated when the triangular arrangement of iced transmission lines is short-circuited, which may lead to the occurrence of adhesion accidents. In order to analyze the vibration law of triangularly arranged iced conductors under the action of short-circuit alternating electrodynamic force, this paper establishes a mathematical model of spatial magnetic field and electrodynamic load of triangularly arranged conductors according to the principle of field strength superposition. The transient solution domain of COMSOL finite element analysis software is used to establish the simulation model of transmission conductor. The variation law of alternating reciprocating load of transmission conductor under short-circuit state is clarified, and the mathematical model of adhesion judgment of triangularly arranged transmission conductor is established. The horizontal displacement and vertical displacement of transmission conductor under different conditions are solved. The results show that: 1) The electrodynamic force generated by short-circuit current changes periodically, and the amplitude will gradually decay. 2) The thicker the conductor icing is, the smaller the electrodynamic force is, and the smaller the displacement of the conductor is; 3) The horizontal displacement and vertical displacement amplitude of the triangular arrangement wire are similar, indicating that when the direction of the electric dynamic load is the same, considering the displacement of the two directions, it is found that the A and C two-phase wires first adhere.

Electromechanical and thermophysical processes in the pulse induction accelerator of plasma formation

Introduction. Work on the creation and throwing of plasma formations is carried out in the world's leading scientific centers in various ways. The creation of a plasma formation with duration of several milliseconds and its acceleration in an open atmospheric environment to a distance of 0.5-0.6 m was achieved. To create plasma, the energy of the primary discharge circuit is used, followed by the acceleration of the gas-plasma formation with the help of the energy of the secondary circuit. Plasma formation is also obtained due to the electric explosion of a conductor in a rapidly decreasing strong magnetic field, etc. The purpose of the article is a theoretical and experimental study of electromechanical and thermophysical processes in a pulsed induction accelerator, which ensures the creation of plasma formation due to thermal ionization as a result of the electric explosion of the conductor and its throwing in the atmospheric environment relative to the inductor. Method. For the analysis of electromechanical and thermophysical processes in the pulse induction accelerator of plasma formation (IIPP), a mathematical model of the accelerator was developed and implemented in the Сomsol Multiphysics software package, in which the anchor does not change its shape and aggregate state during operation and takes into account the parameters of the accelerator distributed in space. Results. Calculated electromechanical and thermal characteristics of the accelerator. It is shown that the temperature rise in the aluminum foil anchor is significantly uneven. The maximum temperature value occurs in the middle part of the foil closer to the outer edge, and this temperature is significantly higher than the boiling point of aluminum. Scientific novelty. Experimental studies of the IIPP were carried out, in which the armature is made of aluminum and copper foil, and the inductor connected to the high-voltage capacitive energy storage device is made in the form of a flat disk spiral. It was established that during the operation of the IIPP, the armature goes into a plasma state and moves vertically upwards, turning into a three-dimensional lump or a pile of small particles that rose to a considerable height relative to the inductor. Experimentally, the characteristic circular circuit of thermal heating of the copper foil of the anchor, which is fixed on a glass-textolite sheet, is shown, which indicates a similar nature of plasma formation. Practical value. The results of experimental studies with an accuracy of up to 15 % coincide with the calculated ones and show the validity of the IIPP concept, in which, due to the high density of the induced current in the armature, thermal ionization occurs as a result of an electric explosion of the conductor with its transition to the plasma state. And the interaction of the plasma formation with the magnetic field of the inductor leads to the appearance of an electrodynamic force that ensures its movement in the open atmospheric environment.

Zero Casimir force in axion electrodynamics and the search for a new force

Zero Casimir force in axion electrodynamics and the search for a new force

Vibration response analysis of iced transmission line under short-circuit alternating electrodynamic force

When a short-circuit fault occurs in an AC transmission line, an alternating reciprocating load that changes periodically with the short-circuit current is generated, increasing the probability of adhesion accidents in the transmission line. To analyze the influence of alternating reciprocating load caused by short-circuit electrodynamic force on the spatial trajectory of iced transmission line vibration, the electrodynamic load is added to the vibration equation of transmission line, and the mathematical model of spatial magnetic field and an electrodynamic load of horizontal arrangement wire is established. The finite element software is used to establish the transmission line model under different short-circuit currents and working conditions. The state of electrodynamic load at each phase wire is clarified at each time. The electrodynamic load is matrixed, and the vibration equation of the transmission line is introduced. After obtaining the spatial displacement of the transmission line, the spatial displacement adhesion mechanism is used to determine whether the transmission line adheres. Clear the easiest adhesion conditions and critical adhesion current.

Progressive technologies of electrophysical treatment for regulation of stress-strain states of elements of welded structures

The development of industry stimulates the development of modern approaches to the optimization of welded structures. The use of pulsed electromagnetic fields, plasma currents, electrodynamic forces and their combined effects is a new trend in engineering practice to improve the mechanical characteristics of metal materials and welded joints (WJ). Treatment with a pulsed electromagnetic field (TwPEMF) is a promising direction for optimizing the stress-strain states (SSS) of welded structures made of non-ferromagnetic metal materials. Using the method of electronic speckle interferometry, the effect of TwPEMF on the SSS of specimens of circumferential WJ with a thickness of δ = 1.0 mm from aluminium AMg6 alloy was investigated. Based on the original procedure using an accelerometer, the kinetics of the action of the force P of the magnetic field pressure on the residual displacements f and SSS of the specimens during their TwPEMF were investigated. TwPEMF of WJ specimens was performed without and with the use of an additional shield made of AMg6 alloy δ = 5.0 mm. It was found that the use of a shield increases the amplitude values of force P by up to two times, which is caused by an increase in the active volume of the conductive medium. At the same time, TwPEMF without and with the use of a shield contributes to the reduction of f values by 2 and 4 times, respectively, and residual SSS by 50 and 80%. On the basis of mathematical modelling, the advantages of using electrodynamic treatment (EDT) of butt WJ δ = 3.0 mm of АMg61 (1561) alloy in the TIG welding process compared to EDT at room temperature (Tk) are substantiated. According to the results of the model verification, it was proved that EDT during TIG contributes to the formation of peak values of residual compressive stresses in the weld zone by 60% more than EDT during Tk. The use of a pulsed barrier discharge (PBD), which generates a low-temperature plasma on the surface of the metal being treated, contributes to the optimization of its structure. An increase in the hardness HV of structural 25KhGNMT steel as a result of its PBD treatment from 420 to 510 units was established, which is accompanied by the dispersion of the metal microstructure.

Inductance and Electrodynamic Forces in Circular Turns with Parallel Axes

With a wireless method of transmitting electrical energy to autonomous objects, a need may arise to use connecting devices with inductively coupled structural elements. When choosing such devices, their effectiveness should be evaluated taking into account the technological and design features of the embodiment. Expressions for mutual inductance and electrodynamic forces with parallel displacement of mating turns and disk coils are considered. Simplified expressions for the derivative of the inductance coefficients in the coordinate characterizing the parallel displacement of the loops are obtained. By using the obtained expressions, the effect of parallel displacement of the loops on the electrodynamic interaction forces can be evaluated. The obtained expressions are verified by numerically comparing them with the exact solution. On this basis, the maximum level of convergence of the results has been determined.

Проблемы электродинамических усилий в индукционных нагревателях

Problems are considered related to electrodynamic forces in the powerful induction heaters of industrial and medium frequency. The methods are given for calculating the forces acting on the heated blanks, inductive coils, and magnetic cores. One of the methods is based on the calculation of the total ponderomotive force acting on the current-carrying conductors and ferromagnetic bodies. To implement these methods, general-purpose computer-aided engineering software based on the finite element method and suitable for building electrothermal models is required. Building of such models is a rather laborious process, and the calculations take a significant amount of time, which does not allow the required number of calculations to be carried out within a reasonable time. Other methods are based on the calculation of the partial derivative of reactive power by the required coordinate. Thus, the corresponding projection of the force on the given axis is calculated. In combination with the subject-oriented 2DELTA coupled electrothermal software, this approach allows to perform the required number of calculations with a suitable for practice of induction heating design accuracy and with significantly less time. Comparative analysis was carried out related to the safety of some types of industrial induction installations used for heating various metals. The technological processes of induction heating of copper, aluminum and some steel grades are considered. The main parameters influencing the negative impact of electrodynamic forces are shown. In particular, when analyzing the axial component of such a force, it was established that the force of friction of the heated ingots against the guides has a significant negative effect. In the case of heating of ferromagnetic ingots, the direction and magnitude of the electrodynamic force are also influenced by the thermal regime. The methods are proposed for solving the problems of ensuring electromechanical safety in the design and tests of induction installations.