Journal of Electrostatics最新文献

英文中文

Uniform electric-field optimal design method using machine learning 利用机器学习的均匀电场优化设计方法

IF 1.9 4区工程技术 Q3 ENGINEERING, ELECTRICAL & ELECTRONIC

Journal of Electrostatics

Pub Date : 2024-11-06 DOI: 10.1016/j.elstat.2024.103990

Zipeng Cheng, Qizheng Ye, Xiaofei Nie, Chengye Li, Wenhua Wu

The demand for uniform electric fields (UEFs) in engineering is very high, particularly in high-voltage devices. The existing methods encounter limitations in terms of optimization region and universality. Herein, we propose a method for designing UEFs based on finite element calculations of electromagnetic fields and machine learning. First, the electric-field distribution of the plate-to-plate electrode structure determined using three electrode-shape parameters (ESPs) is calculated using finite element software and is drawn. Thereafter, a dataset of 2000 images is created with different electric-field strength distributions using various ESPs. Net, we employ image-processing techniques to extract nine statistical features from the gray-level information in the images. Models are trained through machine learning to predict ESPs based on the gray-level features (GLFs). Finally, the electric-field strength distribution image of the expected ideal uniform field is artificially selected. In addition, the ESPs from which the uniform electric-field is produced are predicted by the models. The proposed method provides an accurate solution for optimizing the design of a uniform electric-field and a new approach for solving inverse problems of electric-field. This involves drawing the required electric-field strength distribution image for high-voltage engineering and obtaining the required ESPs.

工程领域对均匀电场（UEF）的要求非常高，尤其是在高压设备中。现有方法在优化区域和普遍性方面存在局限性。在此，我们提出了一种基于电磁场有限元计算和机器学习的均匀电场设计方法。首先，使用有限元软件计算并绘制使用三个电极形状参数（ESP）确定的板对板电极结构的电场分布。随后，我们创建了一个包含 2000 张图像的数据集，这些图像使用不同的 ESP 呈现不同的电场强度分布。然后，我们采用图像处理技术，从图像的灰度信息中提取出九个统计特征。通过机器学习训练模型，根据灰度特征（GLF）预测静电除尘器。最后，人为选择预期理想均匀场的电场强度分布图像。此外，模型还能预测产生均匀电场的 ESP。所提出的方法为优化均匀电场的设计提供了精确的解决方案，也为解决电场逆问题提供了新的方法。这涉及绘制高压工程所需的电场强度分布图像，并获得所需的静电除尘器。

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引用次数: 0

Numerical simulation of spiked electrode electrostatic precipitator 尖电极静电除尘器的数值模拟

IF 1.9 4区工程技术 Q3 ENGINEERING, ELECTRICAL & ELECTRONIC

Journal of Electrostatics

Pub Date : 2024-10-28 DOI: 10.1016/j.elstat.2024.103987

Xiaohua Wang, Hong Su, Biyu Wang, Junyu Tao

The characteristic of the spiked electrode electrostatic precipitator was numerically studied. Complicated electrohydrodynamic flow was observed and vortices were formed in the ESP with the maximum gas velocity 30.9 m/s in this study. The spiked electrode had significant effects on the distribution of electric field and charge density. The corona charge was confined to six semi-ellipsoidal regions around the tips of the spiked electrode, which was 1.04 × 10⁶ μC/m³ at the tip surface. The particle trajectories were complicated due to the EHD flow. High working potential and low gas velocity were beneficial to the removal of particles.

对尖头电极静电除尘器的特性进行了数值研究。在这项研究中，静电除尘器中出现了复杂的电流体力学流动，并形成了涡流，最大气体流速为 30.9 m/s。尖刺电极对电场和电荷密度的分布有显著影响。电晕电荷被限制在尖刺电极尖端周围的六个半椭圆形区域，在尖端表面的电荷密度为 1.04 × 106 μC/m3。粒子轨迹因 EHD 流动而变得复杂。高工作电位和低气体速度有利于颗粒的去除。

引用次数: 0

Ionic wind produced by volume corona discharges and surface dielectric barrier discharges: What role do streamers play? 体积电晕放电和表面介质屏障放电产生的离子风：流线体起什么作用？

IF 1.9 4区工程技术 Q3 ENGINEERING, ELECTRICAL & ELECTRONIC

Journal of Electrostatics

Pub Date : 2024-10-24 DOI: 10.1016/j.elstat.2024.103988

Eric Moreau, Nicolas Benard

The present study compares the ionic wind produced by volume DC and AC corona discharges, and by surface dielectric barrier discharges (DBD). On the one hand, in the case of a volume corona discharge ignited between a high-voltage needle and a grounded plate, our measurements highlight that the ionic wind velocity increases in the presence of positive breakdown streamers. On the other hand, in the case of a surface AC DBD, the ionic wind velocity decreases when streamers occur. Why such a difference? The answer is not easy and the debate remains open. However, one answer would be that the streamers occurring in a volume needle-to-plate discharge leave an abundance of positive ions in the inter-electrode space and that these ions drift because of the electric field, just after the streamer propagation. On the other hand, in the case of a surface DBD, the streamers can leave positive ions in their wake but their heads especially deposit positive ions at the location where they stop propagating, i.e. a few millimetres from the electrode (up to about 10–15 mm). Then this positive space charge deposited at a few millimetres from the active electrode edge on the dielectric surface acts as a screen against the electric field due to the applied high voltage, thus preventing the drift of the ions remaining on the surface of the dielectric, close to the electrode edge. Having said that, the reality is that this explanation is certainly very simplistic compared with the very complex phenomena taking place in these two discharges, particularly at the times when the streamers form and propagate.

本研究比较了体积直流和交流电晕放电以及表面介质阻挡放电（DBD）产生的离子风。一方面，在高压针和接地板之间点燃的体积电晕放电情况下，我们的测量结果表明，离子风的速度在出现正击穿流线时会增加。另一方面，在表面交流 DBD 的情况下，出现流线时离子风速会降低。为什么会出现这种差异？答案并不简单，争论仍未结束。不过，其中一个答案是，在体积针对板放电中出现的流线会在电极间隙中留下大量正离子，这些离子在流线传播后会因电场而漂移。另一方面，在表面 DBD 的情况下，流线会在其尾部留下正离子，但其头部尤其会在停止传播的位置沉积正离子，即距离电极几毫米处（最多约 10-15 毫米）。这样，在电介质表面距离有源电极边缘几毫米处沉积的正空间电荷就起到了屏蔽外加高压所产生的电场的作用，从而阻止了残留在电介质表面靠近电极边缘的离子漂移。尽管如此，与这两种放电中发生的非常复杂的现象相比，特别是在流线形成和传播的时候，这种解释无疑是非常简单的。

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引用次数: 0

Stress due to electric charge density distribution in a dielectric slab 电介质板中电荷密度分布引起的应力

IF 1.9 4区工程技术 Q3 ENGINEERING, ELECTRICAL & ELECTRONIC

Journal of Electrostatics

Pub Date : 2024-10-19 DOI: 10.1016/j.elstat.2024.103982

John H.J. Niederhaus , Joel B. Coley , Antonio L. Levy

The spatial distribution of electric field due to an imposed electric charge density profile in an infinite slab of dielectric material is derived analytically by integrating Gauss’s law. Various charge density distributions are considered, including exponential and power-law forms. The Maxwell stress tensor is used to compute a notional static stress in the material due to the charge density and its electric field. Characteristics of the electric field and stress distributions are computed for example cases in polyethylene, showing that field magnitudes exceeding the dielectric strength would be required in order to achieve a stress exceeding the ultimate tensile strength.

通过对高斯定律进行积分，分析得出了电介质材料无限板中外加电荷密度剖面导致的电场空间分布。考虑了各种电荷密度分布，包括指数和幂律形式。麦克斯韦应力张量用于计算电荷密度及其电场在材料中产生的名义静态应力。以聚乙烯为例计算了电场和应力分布的特征，结果表明，要获得超过极限拉伸强度的应力，需要超过介电强度的电场幅值。

引用次数: 0

Electrostatic potential measurement of floating conductive objects: Some theoretical considerations and experimental results 漂浮导电物体的静电势测量：一些理论考虑和实验结果

IF 1.9 4区工程技术 Q3 ENGINEERING, ELECTRICAL & ELECTRONIC

Journal of Electrostatics

Pub Date : 2024-10-18 DOI: 10.1016/j.elstat.2024.103986

Pedro Llovera-Segovia , Philippe Molinié , Vicente Fuster-Roig , Alfredo Quijano-López

The measurement of electrostatic potentials of floating conductive objects can, in principle, be performed by well-known basic experimental setups. Commercial equipment is readily available and the physical principles underlaying the problem are well established. However, electrostatic measurements require special attention, as significant errors can arise from the influence of the measuring setup or the misinterpretation of the results. First, the specificity of the measuring equipment must be well understood such as the difference between field mills, induction probes and feedback probes (also called electrostatic probes). These instruments create specific boundary conditions around the object being measured such as the introduction of grounded planes or the cancellation of the electric field. This influence is particularly significant when measuring floating objects as, for example, belts and suspended or flying objects. Even when results are provided directly in volts, their interpretation varies greatly depending on the instrument used. In the case of the field mills measurements, a calibration must be performed to convert the measured electric field into the potential of the floating object. This calibration is often performed by applying a known potential to the floating object. However, this procedure may introduce errors in the measured values due to the presence of the high voltage cable used to charge the object. We describe some examples of numerical calculations and show some experimental measurements on a levitating object.

浮动导电物体静电势的测量原则上可以通过众所周知的基本实验装置来完成。商用设备一应俱全，问题所依据的物理原理也已确立。然而，静电测量需要特别注意，因为测量装置的影响或对结果的误解可能会导致重大误差。首先，必须充分了解测量设备的特殊性，例如场磨、感应探头和反馈探头（也称为静电探头）之间的区别。这些仪器会在被测物体周围产生特定的边界条件，例如引入接地平面或消除电场。这种影响在测量浮动物体（如皮带、悬挂或飞行物体）时尤为明显。即使直接以伏特为单位提供结果，其解释也会因所使用的仪器不同而有很大差异。在场强计测量中，必须进行校准，以便将测量到的电场转换为漂浮物体的电势。校准通常是通过对浮动物体施加已知电势来完成。然而，由于存在用于给物体充电的高压电缆，这一过程可能会给测量值带来误差。我们将介绍一些数值计算的例子，并展示对悬浮物体的一些实验测量结果。

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引用次数: 0

Experimental study of electrostatic charging related to prevention of fire and dust explosions in wood processing facilities 与防止木材加工设施火灾和粉尘爆炸有关的静电充电实验研究

IF 1.9 4区工程技术 Q3 ENGINEERING, ELECTRICAL & ELECTRONIC

Journal of Electrostatics

Pub Date : 2024-10-02 DOI: 10.1016/j.elstat.2024.103983

Jiangtian Hou , Guilin Hu , John R. Grace , Xiaotao Bi

To address the concern of fire and dust explosions in wood processing facilities, the charging behavior on wood dust particles and air hoses during the air-blow cleaning operation were investigated. The effective work function, unit weight and surface roughness were key parameters influencing the charge accumulation on air hoses. The use of compressed air with lower velocity and higher moisture content could reduce the charge generation on airborne wood particles. Particle size, shape and wood species affect the charging behavior of wood dust. Conductive surface and moisture could help charges to be dissipated fast from wood dust particles.

为了解决木材加工设施中的火灾和粉尘爆炸问题，研究人员对气吹式清洁操作过程中木屑颗粒和空气软管上的荷电行为进行了调查。有效功函数、单位重量和表面粗糙度是影响空气软管上电荷积累的关键参数。使用速度较低和含水量较高的压缩空气可以减少空气中木质颗粒上的电荷产生。颗粒大小、形状和木材种类会影响木屑的电荷行为。导电表面和水分有助于电荷从木屑颗粒上快速消散。

引用次数: 0

A method of obtaining inception voltage in spark discharge utilizing a current probe 一种利用电流探头获取火花放电起始电压的方法

IF 1.9 4区工程技术 Q3 ENGINEERING, ELECTRICAL & ELECTRONIC

Journal of Electrostatics

Pub Date : 2024-10-01 DOI: 10.1016/j.elstat.2024.103984

Zhiyu Wang, Can Chen, Suijun Yang, Shuliang Ye

There is usually a significant voltage drop on the electrode during the brief delay before spark discharge occurs when the storage capacitance is small (around or below 100 pF). This leads to a decrease in capacitor energy, which may result in an overestimation of the minimum ignition energy (MIE) of dust cloud. A method that utilizes a current probe to obtain the inception discharge voltage was therefore developed. Firstly, the voltage attenuation on the electrode without spark discharge is measured, enabling an accurate calculation of parasitic capacitance. Subsequently, the inception discharge voltage in a spark discharge is calculated based on the measured spark current, thereby enabling the determination of capacitor energy before spark discharge. The results show that the fitted current curves based on the calculated inception discharge voltage exhibited consistency with the actual spark current curves, indicating that the calculated value of inception discharge voltage was consistent with the actual situation. The method effectively addresses challenges associated with measuring the inception discharge voltage in cases of small storage capacitance, which helps to calculate the capacitor energy before spark discharge for MIE testing of dust clouds that are highly sensitive to electrostatic discharge.

当储存电容较小时（约或低于 100 pF），在火花放电发生前的短暂延迟期间，电极上通常会出现明显的电压降。这会导致电容器能量下降，从而可能导致高估尘埃云的最小点火能量（MIE）。因此，我们开发了一种利用电流探头获取起始放电电压的方法。首先，测量没有火花放电时电极上的电压衰减，从而准确计算寄生电容。随后，根据测量到的火花电流计算火花放电中的起始放电电压，从而确定火花放电前的电容器能量。结果表明，根据计算出的起始放电电压拟合的电流曲线与实际火花电流曲线一致，表明起始放电电压的计算值与实际情况相符。该方法有效解决了在存储电容较小的情况下测量起始放电电压的难题，有助于计算电容器在火花放电前的能量，用于对静电放电高度敏感的尘埃云进行 MIE 测试。

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引用次数: 0

Analysis and comparison of streamer discharge characteristics in equipotential live-line work gap and its simplified gaps under positive switching impulse 等电位带电线路工作间隙及其简化间隙在正开关脉冲下的流线放电特性分析与比较

IF 1.9 4区工程技术 Q3 ENGINEERING, ELECTRICAL & ELECTRONIC

Journal of Electrostatics

Pub Date : 2024-10-01 DOI: 10.1016/j.elstat.2024.103985

Yaqi Fang, Hao Zeng, Bingsen Yang, Suhan Mao, Junkang Fang

Equipotential live-line work (EPLW) is crucial for uninterrupted operation and maintenance of extra-high voltage (EHV) and ultra-high voltage (UHV) transmission lines. Determining the minimum approach distance (MAD) for EHV and UHV systems needs a thorough grasp of EPLW gap discharge mechanisms and characteristics for worker protection. Therefore, we conduct positive switching impulse discharge experiments on EPLW gap and its simplified gaps at a gap distance of 3 m, study the discharge development process and streamer inception characteristics of two gaps, and perform comparative analysis. The experimental results show that sim-worker's feet-test tower gap and the bundle conductor + rod-plane gaps (rod electrode with radii of 2.5 cm and 5 cm) occur multiple streamer inception. The bundle conductor + rod electrode with a radius of 8 cm only has one streamer inception. The average inception voltage, inception time delay and its dispersion of bundle conductor + rod electrode will all rise with the size of the electrode. Compared to the bundle conductor + rod electrodes with radii of 2.5 cm and 8 cm, the average streamer inception time delay and inception voltage of sim-worker's feet are only 3.6 % and 5.1 % subtly higher than those of the bundle conductor + rod electrode with a radius of 5 cm, and a high degree of similarity is exhibited in their probability distribution trends of streamer inception time delay. A larger electrode size will increase the boost time delay, statistical time delay, and its dispersion of bundle conductor + rod electrode, they are closer to sim-worker's feet when the radius of bundle conductor + rod electrode is 5 cm.

等电位带电作业（EPLW）对于特高压（EHV）和超高压（UHV）输电线路的不间断运行和维护至关重要。要确定超高压和特高压系统的最小接近距离 (MAD)，就必须全面掌握带电作业间隙放电机制和特性，以保护工人。因此，我们在 3 米间距下对 EPLW 间隙及其简化间隙进行了正开关脉冲放电实验，研究了两种间隙的放电发展过程和流线萌生特性，并进行了对比分析。实验结果表明，模拟工人脚踏试验塔间隙和束状导体 + 杆状平面间隙（杆状电极半径分别为 2.5 厘米和 5 厘米）出现了多次流线萌生。半径为 8 厘米的束导体 + 杆电极仅有一次流线萌发。束状导体+棒状电极的平均萌发电压、萌发时间延迟及其分散性都会随着电极尺寸的增大而增大。与半径分别为 2.5 厘米和 8 厘米的束状导体+棒状电极相比，模拟工人脚的平均流线萌发时间延迟和萌发电压仅比半径为 5 厘米的束状导体+棒状电极略高 3.6 % 和 5.1 %，且两者的流线萌发时间延迟概率分布趋势具有高度相似性。电极尺寸越大，束导体+杆电极的升压延时、统计延时及其分散性越大，当束导体+杆电极半径为 5 cm 时，它们更接近模拟工人的脚。

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引用次数: 0

Advanced image reconstruction for electrostatic tomography in gas-solid two-phase flow based on convolutional autoencoder neural network 基于卷积自动编码器神经网络的先进气固两相流静电断层图像重建技术

IF 1.9 4区工程技术 Q3 ENGINEERING, ELECTRICAL & ELECTRONIC

Journal of Electrostatics

Pub Date : 2024-09-27 DOI: 10.1016/j.elstat.2024.103979

Jiahe Lyu, Xuezhen Cheng, Zhen Song, Jiming Li

The image reconstruction of flowing charged particles in gas-solid two-phase (GSTP) flow can be achieved through electrostatic tomography (EST). Accurate image reconstruction is crucial for detecting the movement patterns of the particles. In order to improve the quality of reconstructed images, a unique convolutional autoencoder neural network (CANN) is proposed. This study uses an image set generated by the linear backprojection (LBP) algorithm to train the CANN, which consists of an encoder and a decoder. The encoder utilizes convolutional and max-pooling layers to reduce the dimensionality of the images and extract key features, while the decoder restores and reconstructs the images through up-sampling and convolutional operations to closely approximate the reference image. To prevent overfitting, dropout layers are introduced after each max-pooling layer in the encoder. To verify the anti-noise capability of the network, Gaussian white noise ranging from 10 dB to 20 dB is added to the test set. The proposed CANN has been validated through simulations and experiments, demonstrating its effectiveness in overcoming noticeable artifacts and noise in reconstructed images when identifying GSTP flow patterns. Furthermore, it shows significant enhancements in imaging outcomes compared to conventional image reconstruction techniques and some current deep learning algorithms.

气固两相流（GSTP）中带电粒子流动的图像重建可通过静电断层扫描（EST）来实现。准确的图像重建对于检测粒子的运动模式至关重要。为了提高重建图像的质量，我们提出了一种独特的卷积自动编码器神经网络（CANN）。本研究使用线性反投影（LBP）算法生成的图像集来训练 CANN，CANN 由编码器和解码器组成。编码器利用卷积层和最大池化层来降低图像的维度并提取关键特征，而解码器则通过上采样和卷积操作来恢复和重建图像，以接近参考图像。为了防止过拟合，在编码器的每个最大池化层之后都引入了剔除层。为了验证网络的抗噪能力，在测试集中加入了 10 dB 到 20 dB 的高斯白噪声。通过模拟和实验验证了所提出的 CANN，证明它在识别 GSTP 流动模式时能有效克服重建图像中的明显伪影和噪声。此外，与传统的图像重建技术和当前的一些深度学习算法相比，它还能显著提高成像效果。

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引用次数: 0

Electrostatic charging of material webs in gravure printing presses 凹版印刷机材料卷筒的静电充电

IF 1.9 4区工程技术 Q3 ENGINEERING, ELECTRICAL & ELECTRONIC

Journal of Electrostatics

Pub Date : 2024-09-19 DOI: 10.1016/j.elstat.2024.103980

Alexander Götz , Armin Wolfram , Wolfgang Schubert

This paper deals with the electrostatic charging of material webs in production machines. Measurements were made with a special measurement setup inside a gravure printing press and the results were analyzed and interpreted. In order to gather as much information as possible, the electric field strength of a free-spanning web was monitored at different positions inside the machine and under different production conditions. The measurement results confirmed theoretical principles and practical experience, such as the fact that the type of material, printing inks, coatings, machine speed, web tension, printing process and corona pretreatment have a significant effect on the level and polarity of the electrostatic charging. During the series of experiments, peak field strengths of up to 300 kV/m resulting from the charge on the web were measured and changes in the sign were detected within a very short period of time.

本文论述了生产设备中材料卷筒纸的静电充电问题。在凹版印刷机内使用特殊的测量装置进行了测量，并对结果进行了分析和解释。为了收集尽可能多的信息，在机器内部的不同位置和不同的生产条件下，对自由伸展的卷筒纸的电场强度进行了监测。测量结果证实了理论原则和实践经验，如材料类型、印刷油墨、涂层、机器速度、卷筒纸张力、印刷工艺和电晕预处理对静电荷的水平和极性有显著影响。在一系列实验中，测量到卷筒纸上的电荷产生的峰值场强高达 300 kV/m，并在很短的时间内检测到符号的变化。

引用次数: 0

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