Electric Field Distribution Research Articles

Analysis of the influence of configuration parameters on the electric field distribution of the main insulation structure of valve‐side winding of converter transformer considering electro‐thermal coupling

AbstractThe variation of configuration parameters in the insulation structure of transformers significantly impacts the distribution of electric fields. Current research on electric field distribution calculations often overlooks the influence of electric field intensity and temperature on this distribution. However, considering that the direct current conductivity of oil‐paper materials is easily affected by both electric field intensity and temperature, any changes in their conductivity will inevitably affect the electric field distribution. Therefore, this paper incorporates the influence of electric field intensity and temperature on the calculation process of the electric field distribution in the main insulation structure of the valve‐side winding. Additionally, it calculates the distribution of multi‐fields for a wide range of structural configuration parameters. Consequently, the influence law of insulation structure configuration parameters on the electric field distribution of the main insulation structure of valve‐side winding for converter transformer when considering electro‐thermal coupling is obtained. This finding can serve as a crucial reference for designing and optimising converter transformers.

Mxene and GaIn Alloy Nanostructures Regulate Zn Surface Ion Deposition for High-Performance Zinc-Ion Battery.

Zinc is an ideal energy storage material because of its low toxicity, nonflammability, and good biocompatibility. However, the commercial application is seriously hindered due to problems such as dendrite growth, hydrogen evolution, and interface passivation caused by "dead zinc" in the process of cyclic deposition. Herein, a nanoscale deposition dispersion model is designed in order to achieve directional deposition and uniform distribution of zinc ions for the growth of interfacial dendrites. Liquid metal GaIn was combined with Mxene for this nanostructure, which provides a rapid ion transfer channel to achieve lower overpotentials, a more uniform electric field distribution, and stronger corrosion resistance in a core-shell structure to achieve interface reaction suppression. The material was coated on the surface of the zinc metal as an artificial protective layer. It has a better cycle life at 1 mA·cm-2 compared with the bare Zn metal anode, achieving a long cycle time of 1100 h and an ultralow voltage lag (28.1 mV). It maintains the stability for 1000 cycles at 1 mA·cm-2 after assembling the complete battery. This provides a way to improve the performance of zinc-ion secondary batteries and paves the way for the next generation of energy storage devices.

Structural Optimization Design of Vacuum Interrupter Based on Transient Electric Field Distribution

AbstractAs the core device of vacuum circuit breaker, the insulation performance of the interrupter is closely related to the internal structure. In this paper, the electric field distribution of arc interrupter under simulated lightning impulse overvoltage is studied. It is found that the instantaneous electric field intensity is at a high level and the electric field uniformity is poor under lightning impulse. In order to further improve the electric field distribution of the interrupter, this paper proposes a method based on the combination of neural network and particle swarm optimization (PSO) to optimize the important structural parameters of the interrupter. A neural network model was established with suspension shield length (L1), suspension shield radius (R1), end shield radius (R2), contact plate thickness (H1) and end shield length (H2) as inputs, and the maximum electric field strength and the uniformity of electric field on both sides of the static and dynamic contacts as outputs, respectively. The structure of the vacuum interrupter was optimized by PSO algorithm. The optimization results show that: When the structural parameters of the vacuum interrupter H1 are 4.6 mm, H2 is 20 mm, R1 is 3.6 mm, R2 is 3.4 mm and L1 is 110 mm, the electric field distribution of the interrupter is obviously improved, and the electric field distribution of the optimized structure can also be well improved under the power frequency operating voltage. Its electric field intensity between the electrode is significantly low. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.

Exploring the Modelling of Gold Anisotropic Nanoparticles’ Optical Properties as a Promising Tool for Detection Systems Design

Gold nanoparticles have been a central topic in the last few decades due to their excellent optical properties that can be exploited in many applications, including food analysis, materials science, and biomedicine. The basis of these unique optical properties is the phenomenon known as localized surface plasmon (LSP), which relays in the collective oscillation of the conduction band electrons in the nanoparticle when excited by electromagnetic radiation. The optical properties of the nanoparticles are critical for selecting the best nanomaterials for each application, a key factor for optimum performance, and can be tuned due to their dependence on the geometry and size of the nanoparticles, as well as the polarization of the light beam. Here, we conducted simulations to study the tunable optical properties and local electric field distribution of three types of gold nanoparticles, cubes (AuNC), boxes (AuNB), and triangular prisms (AuNT), which have relatively simple synthetic routes. Finally, we compared these results with experimental data and described possible synthetic routes to discuss the positive and negative aspects of using each type of nanoparticle for potential applications.

A gallium oxide MESFET transistor with potential barrier layers for high-power and high-frequency applications

Abstract In this article, a novel gallium oxide metal semiconductor field effect transistor (MESFET) is presented. This device is designed for high-power and high-frequency usage and features embedded potential barrier layers on each side of the gate metal within the channel. The gallium oxide semiconductor (Ga2O3) is highly valued in semiconductor technologies because of its large band gap (4.9–4.8 eV) and high breakdown field (6–8 MV cm−1). These properties make it suitable for high-power and high-frequency operations. We call the proposed structure; the potential barrier layers in Gallium Oxide MESFET (PBL-GO-MESFET). The key idea in the PBL-GO-MESFET transistor is embedding the PB layers to control the electric field distribution. Because of the PB layers, an increased breakdown voltage is observed in the PBL-GO-MESFET device, which is in contrast to conventional GO-MESFET (C-GO-MESFET) devices. The simulation findings indicate that the PBL-GO-MESFET transistor surpasses the C-GO-MESFET transistor in terms of breakdown voltage and radio frequency (RF) traits.

The Influence of Iron Particle Contamination on the Breakdown Characteristics of Circulating Mineral Oil under DC Voltage

The presence of metallic particles can lead to the degradation of transformer oil due to the intensification of the electric fields near the conductive components. The primary objective of this research was to investigate the impact of iron impurities on the electrical properties of Mineral Oil (MO), particularly under conditions of continuous flow. Five distinct samples with varying levels of contaminants were carefully prepared for analysis. A specialized chamber was designed to replicate the circulation conditions of oil within an operating transformer. The focus of the investigation was on the breakdown characteristics under DC voltages. The results indicated that higher concentrations of iron impurities were associated with a reduction in breakdown voltage although the circulation of oil exhibited a beneficial effect. To validate these findings, Finite Element Method (FEM)-based simulations were conducted. The analysis of the electric field distribution revealed that iron impurities amplified the electric field intensity, while circulation served to mitigate this effect. Furthermore, the simulations tracking the trajectory of iron particles demonstrated that circulation hindered the particles from reaching the electrodes, thereby diminishing discharge events and lowering the risk of dielectric failure. In conclusion, the circulation of MO enhanced its breakdown voltage, although the presence of iron contamination could still pose a risk under DC voltage conditions.

Probe-type optical fiber sensors for electric field distribution measurement

This paper reports a compact fiber optical electric field (E-field) sensor aiming for the precise detection of transient E-field distributions. Here, a reflective polarization-reciprocal optical path is proposed, which inherently mitigates the temperature-induced birefringence interference of the electro-optical crystal without the need for additional optical elements, thereby facilitating a reduced-size sensing probe. Furthermore, an adaptive particle swarm optimization (A-PSO) algorithm has been utilized for the first time to optimize the insulation structure of the optical E-field sensor, which significantly suppresses field distortion within the sensing region by 50%. This method addresses the technical gap in optical E-field sensor structure optimization, providing an effective means to improve its spatial resolution. The experimental results demonstrate that the proposed sensor exhibits a broad response frequency range from 50 Hz to 15 MHz, with a sensitivity of 0.675 V/kV cm−1. The proposed sensor successfully monitors the spatial distribution of electric fields in the lightning interception region of a lightning rod, thereby validating its effectiveness.

Research on thermal resistance Performance: Broadband solar absorber based on laminated circular ring − disk microstructure

This paper presents a laminated circular-ring-disk (CRDS) solar microstructure absorber constructed based on heat-resistant metals. This absorber achieves an ultra-broadband absorption with a bandwidth of 2171.68 nm in the near-ultraviolet to mid-infrared band, and has three absorption peaks with absorption rates exceeding 96 %, with peak wavelengths of 342.09 nm, 1215.40 nm, and 2032.86 nm respectively. With the finite-difference time-domain method (FDTD), we detected that the average absorption efficiency of this absorber under Atmospheric mass of 1.5(AM 1.5) conditions is as high as 96.05 %, and the average energy loss is only 3.95 %. Meanwhile, the research results of the electric field distribution of the CRDS microstructure show that CRDS effectively promotes the surface plasmon resonance effect between the laminated metal materials. Combined with the research on the top micro-absorption structure materials, we finally determined the structural parameters of the CRDS structure absorber and selected heat-resistant metals nickel (Ni), chromium (Cr), and titanium (Ti). On this basis,we focused on the thermal radiation performance of the absorber and found that it has good adaptability to high-temperature environments. Finally, by comparing the Transverse Electric Wave(TE) and Transverse Magnetic Wave(TM) polarization conditions with the sweep parameter diagrams of 0°-60°, we found that the absorber has excellent angle insensitivity. In view of the above discussions, the CRDS microstructure absorber has good thermal stability, angle insensitivity, and can achieve ultra-broadband perfect absorption from the near-ultraviolet to the mid-infrared band, and has broad application prospects.

Novel NaNbO3-based, ferroelectric ceramics with excellent polarization and electric potential for antibacterial applications

Low surface electric potential (<1V) limits the large-scale commercial application of ferroelectric antibacterial ceramics. We propose a strategy based on charge-balancing doping to enhance polarization and potential in NaNbO3(NN)-based ceramics for disinfection application. The Mg2+ modified NN showed a superior bactericidal effect greater than 80% for 1.5 h and 99.8% for 3 h without heating or ultrasonication, which is superior to other published works. This is mainly due to its excellent surface electric potential of 1.72 V and defect-related discharge current of 141.9 pA compared to NN and Ca2+ modified NN. Ferroelectric properties demonstrated that NN-Mg possesses a lower EC of ∼40 kV/cm and a higher Pr of ∼32 μC/cm2. Furthermore, the combination of XRD, Raman shift, PFM, and permittivity testing suggests that the smaller domain and enhanced ferroelectric properties in NN-Mg originated from amphoteric doping. Finally, simulation results of the electric field distribution indicated that NN-Mg had a stronger attraction or repulsion to bacteria with negatively charged surfaces.

Dense integration of chlorocatechols crosslinked polyphenylene sulfide solid-state separator for Li Metal-Free Batteries

Dry electrode film fabrication technology, known for its environmental friendliness and low energy consumption, is recognized as an effective industrial approach for producing highly dense solid-state electrolytes and pore-free separators. It holds promise for applying thin lithium metal and Li metal-free anodes in ultra-high energy density Li-ions batteries. However, the films produced by this method suffer from issues such as poor toughness, low strength, uneven thickness, and difficulties in rewinding, which limit its widespread adoption in the large-scale manufacturing of lithium batteries. In this study, we propose a hydrothermal process to introduce a chlorocatechol-based cross-linker onto the surface of highly crystalline polyphenylene sulfide (PPS) powder. By employing the dry electrode process, a PPS-based solid-state separator (PPS-SSS) is fabricated, featuring a thin profile (18±2 μm), a smoother surface, and a denser structure, significantly enhancing its mechanical properties. Moreover, the dense integration structure and chlorocatechol groups contribute to a higher Li+ transference number and more effectively inhibit the growth of Li dendrites. Li metal-free batteries, constructed with this separator, a Sn-plated Cu 10 μm foil anode, and a thick high-nickel cathode dry electrode, exhibit high discharge areal and specific capacities (5 mAh cm−2 and 200 mAh g−1, respectively) and pouch battery device energy density exceeding 440 Wh kg−1. Impressively, even in the presence of Cu or Fe powder contamination on the CuSn foil anode or cathode, this separator can still achieve uniform electric field distribution and lithium deposition, demonstrating good cycle stability.

Experimental measurement of electric field near the insulator string

This paper explores the electric field distribution near a string of six NJ120 high voltage insulators through experimental measurements under various conditions. Using a distributed capacitance method with custom probes connected to an Arduino-based system, tests were conducted on clean and polluted insulators. Pollution was simulated using a tuf-based solution with conductivities ranging from 0.5 to 1.97 mS/cm. Measurements were taken at 13 heights and four distances (1 to1.75 m) under applied AC voltages of 15 to 80 kV. The study also investigates the effects of damaged insulators, placed at different positions (near the high voltage terminal, in the middle, and near the ground), as well as the role of guard rings in improving field uniformity. Results indicate that pollution and damaged insulators significantly increased field intensity, particularly near the high voltage terminal. Guard rings effectively reduced field peaks, with larger radii and optimal placement providing the best performance. These findings contribute to optimizing high voltage insulator design for enhanced reliability.

Multifunctional High-Entropy Alloy Nanolayer Toward Long-Life Anode-Free Sodium Metal Battery.

Anode-free sodium metal batteries (AFSMBs) hold great promise due to high energy density and low cost. Unfortunately, their practical applications are hindered by poor cycling stability, which is attributed to Na dendrite growth and inferior Na plating/stripping reversibility on conventional sodiophobic current collectors. Here, a thin high-entropy alloy (HEA, NbMoTaWV) interfacial layer composed of densely packed nanoplates is constructed on commercial aluminum foil (NbMoTaWV@Al) for AFSMBs. The enhanced sodiophilicity of the HEA greatly reduces Na nucleation barrier with low nucleation overpotential. Simultaneously, abundant active sites of the HEA can boost interfacial reaction kinetics and guide uniform Na deposition. Furthermore, plentiful HEA nanoplates can homogenize electric field distribution and decrease the local current density. Benefiting from the advantageous properties of NbMoTaWV@Al, outstanding electrochemical performances, including an average Coulombic efficiency of 99.5% over 1000 cycles at 2 mA cm-2/2 mAh cm-2 in asymmetric cells, alongside a small overpotential (10 mV at 1 mA cm-2) and a long lifespan of 2500 cycles in symmetric cells, are achieved. More impressively, the anode-free NbMoTaWV@Al||Na3V2(PO4)3 batteries display superior cycling stability over 300 cycles. This work presents an efficient method of employing multifunctional HEA materials to manipulate the interfacial properties of current collector for high-performance AFSMBs.

A bi-directional metamaterial perfect absorber based on gold grating and TiO2-InAs normal hexagonal pattern film

We present and study a bidirectional metamaterial-perfect absorber based on TiO2-InAs regular hexagonal pattern thin films and gold grating. We employ the finite difference time domain approach for simulation. Multi-narrowband perfect absorption and ultra-wideband perfect absorption can alternate as the light source's direction changes. Four narrow-band absorption peaks developed at 987 nm, 1188 nm, 1510 nm, and 2091 nm, respectively, when the incident light struck the bottom. The corresponding absorption efficiencies were 99.69 %, 99.41 %, 98.54 %, and 98.97 %. The broadband region displays the properties of perfect absorption when incident light strikes the top. It should be noted that it is not affected by the polarization or angle of the incidence. With an average absorption efficiency of 96.02 %, the structure attains over 90 % absorption in the 3023 nm range (424–3447 nm). Second, the weighted absorption efficiency of the full spectrum is as high as 96.84 %, and the AM 1.5 solar radiation spectrum and the solar absorption spectrum are strongly coincident. Furthermore, the computation results show that the thermal radiation efficiency is greater than 95 % between 300 K and 1500 K. The electric field distribution revealed that the Fabry-Perot cavity resonance within the film, the surface plasmon resonance (SPR) on the surface of the InAs and TiO2 regular hexagonal pattern films, the interstitial mode excitation between the films, and the excitation cavity coupling between cells of each unit were primarily responsible for the perfect absorption of broadband. The high-order resonant coupling in the FP cavity and the strong coupling between the local surface plasmon resonance and the FP cavity resonance in the metal grating's slit are the primary causes of the narrow band's perfect absorption. The suggested bidirectional metamaterial perfect absorber has significant promise for use in the disciplines of sensing, solar energy absorption, photoelectric detection, and photothermal conversion, as evidenced by its superb absorption and thermal radiation characteristics.

Optimization of Electron Beams for Ion Bombardment Secondary Emission Electron Gun

Abstract Electron beam fluorescence technology is an advanced non-contact measurement in rarefied flow fields, the fluorescence signal intensity is positively correlated with the electron beam current. The ion bombardment secondary emission electron gun is suitable for the technology. To enhance the beam current, COMSOL simulations and analyses were con-ducted to examine plasma density distribution in the discharge chamber under the effects of various conditions and the electric field distribution between the cathode and the spacer gap. The anode shape and discharge pressure conditions were optimized to increase plasma density. Additionally, an improved spacer structure was designed with the dual purpose of enhancing the electric field distribution between the cathode-spacer gap and improving vacuum dif-ferential effects. This design modification aims to increase the pass rate of secondary elec-trons. Both simulation and experimental results demonstrated that the performance of the optimized electron gun was effectively enhanced. When the electrode voltage remains con-stant and the discharge gas pressure is adjusted to around 8 Pa, the maximum beam current was increased from 0.9mA to 1.6 mA.

ЕЛЕКТРОСТАТИЧНЕ ПОЛЕ В КАМЕРІ БАР’ЄРНОГО РОЗРЯДУ ДЛЯ ОЧИЩЕННЯ ВОДИ З УРАХУВАННЯМ ОКРЕМИХ ВОДНИХ КРАПЕЛЬ

The use of pulsed dielectric barrier discharge (DBD) for water purification via low-temperature plasma (LTP) is a promising technology. DBD enables the purification of water in a droplet-film state from organic contaminants by generating highly reactive molecules (OH radicals, O, H2O2, and O3 molecules) produced in LTP upon contact with water. A two-dimensional model was developed to calculate the electrostatic field in the DBD discharge chamber (DC), which includes two electrodes, a dielectric barrier, two water droplets or streams in the air gap, and water films. The model employs Laplace’s equation for the electrostatic field with periodic boundary conditions. Expressions were proposed for determining the length of the symmetric part of the DC and setting the voltage on the electrodes with a constant droplet surface area and a constant average electric field intensity in the air gap, independent of droplet radius. The study investigates the dependence of the electrostatic field energy and DC capacitance on the droplet radius and their mutual positioning along the DC length. Changes in electrode voltage and droplet density per unit DC length relative to droplet radius are demonstrated. An analysis of the electric field distribution, DC capacitance, and stored energy was conducted. The average electric field intensity on the surfaces of droplets and water films was examined. The electric forces acting on the droplets were determined using Maxwell's stress tensor. An expression was derived for calculating the recommended amount of water in the form of droplets or streams per unit dimensions of the DC to achieve a more uniform distribution of the electric field intensity within the DC and to minimize the impact of electric forces on the droplets. Ref. 18, fig. 7.

Analysis of electric field and leakage current of glass and porcelain insulators under clean and polluted conditions: A comparative study of three profiles

Electric field (EF) enhancement in insulating systems may occur due to both internal and external factors including inefficient design, manufacturing defects, and depositions of pollutants. Consequently, phenomena like partial discharge, unexpected flashover, and even breakdown of the insulator may take place. In this work, aiming to suggest relatively better performance, a comparative study of porcelain and glass insulators under clean and polluted conditions was conducted using finite element-based software, COMSOL Multiphysics. Three profiles of both the insulators namely, standard, anti-fog, and open were modelled, and the effects of their geometry and varying electric conductivity of the surrounding air were analyzed on EF distribution and leakage current (LC). These parameters were also investigated under the deposition of water droplets and various pollution scenarios. Results of the performed computations demonstrated that by making air conductivity high, LC enhanced significantly while EF was affected the least. The presence of water droplets in the vicinity of live electrode and deposition of pollution near the end fittings created the strongest impact on EF distribution. Among the studied configurations, standard profile of porcelain material appeared to be the most promising for suppressing effects of the simulated stresses.

Unlocking electrodialysis efficiency with spacer mesh geometry and material conductivity via finite element analysis

AbstractSpacer meshes in electrodialysis (ED) play a crucial role in influencing fluid and electric field distributions during mass transfer. This study employed finite element analysis using real‐world parameters to explore how spacer mesh geometry and material affect mass transport. Comparisons among different wire mesh configurations revealed increased fluid velocity near mesh wires and reduced electric field intensity nearby, enhancing overall transport efficiency. Increasing mesh count or wire diameter notably improves transport, with optimal results achieved when wire orientation aligns with fluid flow. Additionally, the study showed that spacer mesh conductivity significantly influences ED transport, particularly when it exceeds the conductivity of the solution. These findings advance the design and application of spacer meshes, offering valuable insights for future developments in ED technology.

Quantification of Interfacial Charges in Multilayered Nanocapacitors by Operando Electron Holography.

Interfaces in heterostructures play a major role in the functionality of electronic devices. Phenomena such as charge trapping/detrapping at interfaces under electric field affect the dynamics of metal/oxide/metal capacitors and metal/oxide/semiconductor transistors used for memory and logic applications. Charge traps are also key for the stabilization of a ferroelectric polarization and its ability to switch in ferroelectric devices such as ferroelectric tunnel junctions (FTJs). However, electric-field induced charging phenomena remain unclear even in conventional dielectric heterostructures due to a lack of direct measurement methods. Here, it is shown how operando off-axis electron holography can be used to quantify the charges trapped at the dielectric/dielectric interfaces as well as metal/dielectric interfaces in HfO2- and Al2O3-based nanocapacitors. By mapping the electrostatic potential at sub-nanometer spatial resolution while applying a bias, it is demonstrated that these interfaces present a high density of trapped charges, which strongly influence the electric field distribution within the device. The unprecedented sensitivity of the electron holography experiments coupled with numerical simulations highlights for the first time the linear relationship between the trapped charges at each interface and the applied bias, and the effect of the trapped charges on the local electrical behavior.

Comparative analysis of capacitorless DRAM performance according to stacked junctionless gate-all-around structures

The characteristic comparison of the capacitor-less DRAMs in the structural form variation is investigated. Based on the simulation results of the three basic structures, such as circular, square, and rectangular nanosheets, the gate length (Lg), channel thickness (Tsi), and width of the nanosheet (Wsi) are considered as the main factors in design and the characteristic variations are verified according to the junctionless (JL) gate-all-around (GAA) geometry factors. The channel thickness is a major factor that has a major influence on the sensing margin and the retention time, which are important characteristics of DRAM. The thinner the thickness, the more deteriorated the sensing margin is confirmed. Retention time is due to the influence of the electric field distribution of the JL GAA structure, resulting in differences in structure. Finally, the rectangular type nanosheet is implemented in the stacked structure. As the number of stacks increases, the effective channel width increases compared to the layout footprint. In addition, by stacking vertically, the area where holes can be stored increases. Therefore, the sensing margin tends to increase as the number of stacks increases. However, the difference in diffusion due to the difference in the initially stored hole density, the retention time deteriorates as the number of stacks increases

A sustainable waveguide-based design strategy for improving the energy efficiency of microwave hybrid heating systems: A combined theoretical and multi-physics simulation approach

The microwave hybrid heating (MHH) based processing has emerged as energy-efficient and productive manufacturing process. The efficiency of MHH depends upon the ability of waveguide system to transmit the electromagnetic radiation with minimal loss. Thus to improve the efficiency of MHH it is of paramount importance to understand the potential of waveguide systems. In the present work, the influence of different waveguide systems, their positioning, and different modes of operation on MHH efficiency were studied via theoretical and simulation investigations followed by experimental validation. Based on the study, the optimum waveguide system was identified as WR430. To assess the efficiency and effectiveness of the waveguide positioning on MHH, 12 different locations were considered, and the optimum location was identified as (+35, −35), with a maximum microwave utilization efficiency of 44.5 %. Subsequently, the simulation model (1049 °C) was validated using experimental data (1017 °C) with an error of less than 10 %. Also, MHH is sensitive to different waveguide operating modes, SiC susceptor positioning and microwave power. A microwave cavity operating with two waveguides on both sides is found to provide optimum results in terms of heating uniformity, electric field distribution, and microwave energy absorption. The SiC susceptor positioned at the centre of the alumina refractory yields maximum heat evolution of 1020 °C. In addition, as the microwave power grows, the temperature differential also increases, implying thermal heterogeneity inside the SiC susceptor. Thus, low microwave power is identified for improved thermal uniformity and energy efficiency, while high power is proven for rapid differential microwave heating.