Development of three-dimensional electric field computation system by surface charge method

This paper describes development of three-dimensional electric field computation system by surface charge method. Using this system, both potential and electric field in the case which includes resistance or true electric charge can be calculated. And this system is able to be connected to the pre-post processors, which is useful for us to make arbitrary shape and to display results of analysis.     

基于模拟电荷法的变电站工频电场仿真分析

随着供电需求的增大,超高压变电站越来越接近公众活动区域,变电站站内的电场分布情况也显得越来越重要。本文提出改进的模拟电荷法,推导了带电体周围的工频电场计算公式。通过对500k V变电站进行模型建立及简化,编程计算出站内离地1.5m处的工频电场强度;采用CDEGS软件对重庆某500k V变电站进行仿真计算,将仿真结果和实测值与本文算法的计算结果进行对比,验证了本文算法的正确性与有效性。最后选取该变电站内三条路径,计算分析该处工频电场强度的分布情况,为深入研究变电站的工频电场分布提供参考。     

Evaluation method of computational error for electric field analysis by a surface charge method

In this paper, an evaluation method of computational error for the electric field analysis by a surface charge method is proposed. In the method, an approximate equation of the smoothness of the electric field distribution is used to evaluate the computational error. In two‐dimensional and axisymmetric problems, the approximate equation of the smoothness is expressed by the second derivative form of the surface charge density with respect to the distance along the surface. Furthermore, the smoothness is expanded to three‐dimensional problems and a general form of the equation for the smoothness is obtained. The applicability of the proposed method is verified by computation results of a two‐sphere model and a hyperboloid model. © 1998 Scripta Technica, Electr Eng Jpn, 126(1): 7–14, 1999     

Analysis of electric field induced by ELF magnetic field utilizing fast‐multipole surface‐charge simulation method for voxel data

This paper presents a fast‐multipole surface‐charge‐simulation method for calculating three‐dimensional Laplacian fields in voxel models. This method treats a surface of a voxel that has different inside and outside conductivities as a surface element of the indirect BEM (boundary element method). The main features of the proposed method are as follows. (1) An O(D²) performance in the memory capacity and operation cost is provided by applying the diagonal form fast multipole method (FMM), when the number of voxels is about D³. (2) The boundary matching is imposed by the continuity of the total flux passing through each element, which guarantees the solution globally satisfying Gauss's law; therefore the solution is globally stabilized. This method is successfully applied to calculate the electric field induced by an applied homogeneous ELF (extremely low frequency) magnetic field in a human head model that has 1 mm ×1 mm 1 mm voxel size. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 165(4): 1–10, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20529     

表面电荷法在复杂地势下超高压输电线路的工频电场计算

为了更准确地研究超高压输电线路穿越较复杂地区时的工频电场,利用表面电荷法的思想,给出了该方法的实施步骤并进行了验证。综合考虑了输电线路的弧垂,建立了复杂地势三角坡和凸面的三维模型,并仿真分析了其周围工频电场的分布。研究结果表明:1三角坡和凸面对输电线路下的工频电场影响较明显;2随着三角坡坡角的增大场强值畸变越大,且使临近三角坡坡脚处场强值减少越大;3不同的输电线排列方式下,复杂地势周围的工频电场畸变不同,倒三角排列下其值畸变大于其他排列。该仿真结果可为复杂地势下输电线路的架设提供参考依据。     

Electric field calculation in composite dielectrics by surface charge method based on electric flux continuity condition

We propose a new surface charge method based on the continuity of electric flux passing through each partial area on the dielectric boundary. N partial areas divided on the boundary give the boundary equations for solving N unknown variables representing the surface charge density distribution. The electric flux is numerically calculated by integrating the normal component of electric flux density on each partial area. This method permits us to exclude the singularity of edge parts from the boundary equations because these parts do not contribute to the integration area. In this paper, we apply first‐order functions to simulate both triangular surface shape and charge density distribution on its surface as well. First, we have computed the electric field for a spherical dielectric under a uniform field. The calculated results show that the accuracy of the electric field at the spherical center is almost equal to the accuracy of the total surface area of the polygon which represents the sphere. Furthermore, this method has improved the accuracy of the field by about one order compared with the conventional surface charge methods. Second, we have computed the electric field for a dielectric human model under a uniform field. The calculated results demonstrates that the proposed method works well for a complicated shaped object with a dielectric constant greatly different from that of an ambient medium. © 2002 Scripta Technica, Electr Eng Jpn, 138(4): 10–17, 2002; DOI 10.1002/eej.1133     

基于嵌入式平台的分布式光伏发电监测系统

1光伏发电监测系统光伏发电也称太阳能发电,即利用太阳能级半导体电子器件吸收太阳光辐射能,并使之转换为电能。光伏发电系统主要由太阳能电池、蓄电池、控制器和逆变器构成。蓬勃发展的光伏产业,一方面带动了相关技术领域的快速发展,另一方面也对光伏配套产业链提出了更高的要求。为保证光伏发电系统可靠稳定运行,需要有完备的发电监测系统进行长期监测,并能根据实时监测结果提供完善     

Ways to calculate electric fields in traction electric motor insulation by equivalent charge method

A procedure permitting one to calculate the electric fields in multilayer insulation based on the equivalent charge method is presented. Consideration of the new algorithm shows its fast response and proper accuracy.     

基于表面电荷法的输电线路表面电场强度计算

三相输电线路导线表面电荷的分布是不均匀的,各点电场强度的大小也不同.文中采用表面电荷法计算导线表面的电荷密度,然后求出导线表面各点的最大电场强度值.计算方法能够反映出电荷密度及电场强度沿导线圆周分布的情况,根据计算结果优化高压输电线路的布置.     

粒子群优化模拟电荷法在HGIS工频电场计算中的应用

近年来,复合型气体绝缘组合开关设备（HGIS）以其造价适中、占地面积小、运行安全可靠等优点,在我国超高压变电站建设中得到越来越多的应用。研究分析HGIS工频电场分布规律,对智能变电站设计与建设、电磁环境评估、消除民众对输变电工程电磁辐射不必要的担忧等有着重要的指导和现实意义。鉴于传统模拟电荷法（CSM）在布点和校验上过于繁琐,难以应对复杂计算场景的问题,本文提出将粒子群优化算法（PSO）和传统模拟电荷法结合,形成优化模拟电荷法（PSO-CSM）,并将其应用到500kV HGIS配电装置区工频电场的计算与分析中,计算分析配电装置区各主要设备对工频电场的影响以及整个配电装置区工频电场分布状况,并提出了电场优化的相关建议和改进措施。     

500kV超高压输电线下山坡周围工频电场分析

在输电线下电场的计算中,普遍将输电线下地面视为平地,而忽略了不规则地面对输电线下电场计算的影响。为此建立了山坡周围工频电场的计算模型,基于模拟电荷法分析了平地及山坡表面的电场分布,并分析了影响山坡周围电场分布的因素。研究表明,山坡对输电线下电场分布有明显影响,电场在靠近山坡坡脚处逐渐减小,在随着山坡高度的增加而逐渐上升,在坡顶处电场发生畸变。山坡的角度、高度、输电线与山坡的相对位置及输电线的剖分密度对其周围电场计算都会产生影响,角度越大,高度越高,在山坡顶部电场的畸变越明显。输电线与山坡之间的夹角越大,在坡脚处电场减弱的趋势越明显。     

基于模拟电荷和边界元法的变电站工频电场分布仿真研究

本文提出了一种模拟电荷法和边界元法相结合的方法,将变电站内设备的影响考虑进去,可更加准确地确定变电站内工频电场分布,并且本文采用了合理简化剖分的方法,减少了冗长的叠加过程,在保证了计算精度的同时,大大缩短了计算时间,为变电站内工频电场计算提供了一种快速有效的方法.本文仿真结果与变电站实测结果基本一致,证明该方法能够用于变电站工频电场分布的预测.     

Electric field calculation in composite dielectrics by a curved triangular surface charge method

This paper describes a triangular surface charge method (TSCM) called (3,1)‐TSCM, which uses curved surface elements for calculating electric fields in composite dielectrics. The boundary element utilizes a cubic shape function with nine degrees of freedom and a linear function for representing the charge density on its surface. Conventional SCMs, including the (3,1)‐TSCM, show a very large relative error in the composite dielectrics where the permittivity is much higher in one medium than in the other. A modified method called the β method can suppress such relative errors, which expresses electric fields by surface charges without subtraction causing large relative errors. We have applied the β method to the (3,1)‐TSCM and calculated electric fields for a spherical dielectric under a uniform field. The calculated results show that the (3,1)‐TSCM improves the accuracy of the electric field by more than one order compared with the method using flat surface elements with constant charge density on each element. Furthermore, the β method completely suppresses the divergence of relative errors even when the ratio of the permittivity of two media reaches 10¹⁰. © 2001 Scripta Technica, Electr Eng Jpn, 136(1): 1–8, 2001     

变压器电场分析方法研究

指出了传统电场分析方法的缺陷，对线圈端部实际承受的电场强度的计算进行了分析。以安全裕度统计法定义为前提，完全可以把线圈间的电场强度(不含端部，中断点等特殊点)简化为平板电容器形式的场强计算。     

一种基于矢量电场的多电极电场梯度计算优化方法研究

通过对变电站中电气设备电场梯度信息检测计算方法进行研究,结合矢量电场多电极梯度信息,使用压缩感知贪婪重构算法对电场检测计算方法进行优化,对电场梯度信息进行有效识别,提高电压等级检测判断的准确率。该方法通过分析带电体周围电场信息,能够准确地计算出高电压导体周围的电场分布和电压等级。通过在110 k V变电站复杂工频电场环境中进行试验,获取带电载体一个间隔的场强分布。实验分析表明,该方法可以有效提高带电载体电压等级的检测能力和对带电体周围电场信息的响应速度,提高了工作人员在复杂工频电场环境下工作的安全性。     

Electric field calculation in composite dielectrics by first‐order triangular surface charge method

This paper proposes a technique for calculating electric fields in composite dielectrics by the first‐order triangular surface charge method. The proposed technique utilizes two kinds of triangular elements, namely, conforming and nonconforming elements: these are elements whose charge density is continuous and discontinuous between the neighboring elements, respectively. We basically apply nonconforming elements at the edges of a polyhedral shape where the normal component of electric field cannot be fixed. We have computed the electric field for a spherical or a rectangular solid dielectric in the presence of a uniform field. Comparison shows that the proposed first‐order method works better than the zeroth‐order one, and that, in particular, the combined use of conforming and nonconforming elements produces the highest accuracy. © 2001 Scripta Technica, Electr Eng Jpn, 135(1): 8–14, 2001     

空间电荷及金属颗粒对换流变阀侧套管的电场分布影响

换流变压器阀侧套管承受交、直流复合电压,对套管的性能和质量有严格的要求。直流电压下,不同介质界面处空间电荷积聚会引起局部电场的畸变,金属颗粒的存在也会大幅提高局部场强,二者均会降低套管的绝缘性能。文中根据换流变压器阀侧套管的结构,采用有限元分析软件,建立了阀侧套管的仿真模型,分析了加入空间电荷后不同类型电压下套管的电场分布以及金属颗粒对局部电场的影响。结果表明,直流电压下介质界面处空间电荷更容易积聚,交直流复合电压下空间电荷能够引发套管内部局部电场的畸变。与交流电压相比,直流电压下金属颗粒对局部电场的畸变程度影响更大,在SF₆气体中金属颗粒对电场畸变程度的影响大小与其所在位置的关系不大。     

110kV合成绝缘子沿面电场分布的研究

在建立数学模型的基础上计算合成绝缘子沿面场强，利用二次插值有限元法计算ll0kV合成绝缘子电场分布和相同边界条件的空气间隙的电场分布情况；并将不同边界条件下的合成绝缘子的电场分布计算结果进行比较分析，结果表明在改善绝缘子电场分布的三种方法中以外加装均压环的效果最好。     

基于Pockels效应的大气电场测量研究

为解决常用场磨式大气电场仪体积大、机械磨损严重、易受电磁干扰、测量带宽窄等问题,在研究分析Pockels效应原理的基础上,提出应用Pockels效应来测量大气电场的方法。对晶体、光源的选择及传感器设计中出现的问题进行了分析,设计了一种基于Pockels效应原理的脉冲电场传感器,该传感系统包括稳定高效的光源、Pockels晶体探头、数据采集及处理电路。通过模拟仿真,说明了这种测量方法是可行的,为进一步研制大气电场测量传感器,提高其性能提供了理论依据。     

ADSS光缆与高压输电线路同杆并架全程三维电场分析与光缆挂点优化设计软件

详细给出了沿高压输电线路加挂ADSS光缆时电场的空间三维计算原理。为了优化计算，提出了线电荷与点电荷相结合的等效电荷法。在此基础上编制了分析输电线路任意截面及沿ADSS光缆走向的电位、场强分布的三维计算软件。此外，该程序还能考虑转角、换位、舞动等工况。对不同塔型的计算结果表明：软件中采用的算法合理，所得结果对ADSS的挂点选择和优化具有参考价值。