An effective modelling method to analyze the electric field aroundtransmission lines and substations using a generalized finite linecharge

For the rather complicated and time-consuming three-dimensional electric field calculation in the vicinity of transmission lines and substations, this paper proposes an effective numerical calculation method based on the charge simulation method (CSM). In order to better represent nonuniform charge distribution on an electrode, it is subdivided into small segments with linear charge density. Each segment with linear charge density can be easily represented by a generalized finite line type of charge whose expressions for potential and electric field were analytically derived and which was named “finite slant line charge” in this paper. As for the arrangement of small segments of a subdivided electrode, it has been found that the unequally spaced arrangement method is superior to the equally spaced one. In order to arrange segments fast and effectively, effective formulas were derived from multiple regression analysis of many simulations. The proposed method is applied to the electric field calculation around the transmission lines with significant change in direction and substation busbars     

特高压输电线路分裂导线表面电场特性分析

特高压输电线路能减小走廊面积,有效提高单位输电线路走廊宽度的输电容量,从而提高输电线路的经济效益。特高压输电线路常采用多分裂导线,导线表面电场强度的计算精确度直接影响导线的合理选型和布置。为此,以有限元法为理论基础,以COMSOL Multiphysics软件为仿真工具,以1000 kV特高压交流输电线路为研究对象,建立典型特高压交流输电线路的二维静电场仿真模型,研究分析分裂导线在水平排列、同塔双回、正三角对称、倒三角紧凑型对称布置方式下周围空间电场的分布,以及地面是否水平、是否有杆塔等因素对电场分布的影响。分析结果可以为特高压交流输电线路的设计提供一定的参考。     

高压真空器件内绝缘击穿及老炼处理

为解决一种工作在几μs宽高压脉冲下高压真空器件的击穿问题,据其绝缘结构特点确定计算边界条件并用有限元法计算了阴极区域的电场分布;采用高压真空器件解剖、扫描电镜分析和高压脉冲耐压试验分析了高压真空器件内的真空击穿、陶瓷击穿。结果证明采取高压脉冲老炼方法对器件加固后,可减少器件的高压击穿几率,提高耐高压能力和工作可靠性。     

动车组车顶高压电器箱的电场计算及优化设计

集成化的动车组车顶高压电器箱,其箱内电气设备布局非常紧凑,可能造成某些设备的金具表面电场集中,导致电晕放电。建立动车组高压电器箱的三维有限元计算模型:在正常工况(额定工作电压)下,基于静电场分析箱内整体电场的分布规律;在异常工况(标准雷电冲击电压)下,基于瞬态电场分析箱内整体电场分布及其随时间的变化规律。针对高压电器箱内表面场强较集中的金属部件,分别进行电场调整:采用改变电极形状的方法,调整高压隔离开关的表面电场;采用包裹绝缘护套的方法,调整电压互感器汇流排的表面电场;采用增设开口均压环的方法,优化真空断路器上/下刀片的表面电场,并借助正交化实验设计方法,确定开口均压环的最佳设计参数。最后,通过悬浮金属的电位测量试验,验证有限元计算的正确性。文中的分析计算和结构优化方法可为高压电器箱的工程设计提供参考。     

Verǵleichende Feldberechnunǵen und Optimierunǵ in Elektrodensystemen von Hochspannunǵsanlaǵen

Übersicht Zwei numerische Feldberechnungsmethoden —die Finite-Elemente-Methode und das Ersatzladungsverfahren — werden am Beispiel eines konkreten Elektrodensystems miteinander verglichen. Bei der Finite-Elemente-Methode wird mit Dreieckelementen und einem Polynomansatz gearbeitet, beim Ersatzladungsverfahren mit diskreten Ladungen und Flächenladungen, die lineare Geometrie und Ladungsdichteverlauf aufweisen. In den Vergleich wird auch ein neues Optimierungsverfahren für Elektrodenkonturen einbezogen, mit dem das Elektrodensystem bezüglich betragsminimaler und konstanter Feldstärke optimiert wird. — Die Ergebnisse bezüglich Potential-und Feldverteilung auf Elektrodenoberflächen und Grenzschichten werden diskutiert, auf ihre Ursachen untersucht und die benötigten Rechenzeiten und Speicherräume sowie der notwendige Adaptionsaufwand der Verfahren gegenübergestellt.

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Determination of electric fields using different computational methods and optimisation of electrode configurations in high-voltage equipment

Contents The charge simulation method and the finite-element method are used in practice to calculate the electric field strength of high-voltage equipment. This paper reports on a comparative study of these two methods for a high-voltage electrode configuration with dielectric spacer. —Discrete charges and surface charges are used for the charge simulation method. As approximate potential function in an element, first and second-degree polynomials are used for the finite-element method. The study also includes a new method for optimisation of electrode contures. — The electric field strength on the original electrode and the optimum electrode, normal and tangential electric field components along the spacer surface are calculated and compared. The results are discussed, and the computing time and core memories are examined.

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Die Autoren danken Prof. Dr.-Ing. K. Möller für wertvolle Anregungen und Hilfen.     

UHV串联式TV高压隔离部分的有限元分析及优化

用于超高压和特高压的电压互感器可采用多台电压互感器在一次侧和二次侧串联实现,一次绕组的串联结构与传统的串级结构相似,二次侧的串联结构需要使用高压隔离电压互感器,目前这种互感器还没有设计的经验。为此以1 000 kV串联式标准电压互感器为例,用有限元分析软件ANSYS对高压隔离互感器的三维电场分布进行了数值模拟计算和性能优化。结果表明,基于有限元法的数值模拟是分析和设计串联式电压互感器的有效手段,经优化设计后的高压隔离互感器能够同时满足绝缘和精度方面的要求,优化结果为更高电压等级的串联式电压互感器的设计和制造提供了可靠的、科学的数据。     

优化模拟电流法计算超高压输电线路三维磁场

为了获得更准确的输电线路下方磁场的三维分布,使用智能优化算法对模拟电流法中模拟电流的个数与位置参数进行 寻优,解决了普通模拟电流法中模拟电流的位置和个数只能依靠经验来确定的问题,从而提高计算精度。 建立基于输电线路实 际物理形状的三维计算模型,通过不同方法计算上海市松江区洞泾-泗泾 500 kV 线路的三维磁场分布。 将计算结果与实际测 量结果进行对比,结果表明优化模拟电流法的计算误差为 4. 54%,比传统计算方法的 12. 21%降低了 7. 67%。 为优化模拟电流 法计算输电线路的磁场分布提供理论基础,并对高压输电线路的建设有理论指导意义。     

Generalized charge simulation method for the calculation of the electric field in high voltage substations

This paper deals with the calculation of the electric field strength in high voltage (HV) substations comprising complex geometrical structures. Generalized charge simulation method is proposed for improving the precision of the calculation of the electric field strength. The objective of this analysis is to examine the influence of towers, HV apparatus and fences on the spatial electric field distribution. For this purpose, a three-dimensional generalized model of HV substation has been developed, including phase conductors, bypass busbars, HV apparatus, fences and towers (denoted as Full model). The obtained results of the calculation of the electric field strength are compared with the Simplified model, which only includes phase conductors connected to HV network. Verification of the proposed Full model performed by comparing the calculated and in-field measured values of the electric field strength within HV substations and in their vicinity gives very promising results.     

Premises for the mathematical modeling of the combinedcorona-electrostatic field of roll-type separators

Corona and induction charging mechanisms are frequently associated in modern roll-type electrostatic separators. Various electrode configurations have been proposed and numerous attempts have been made in order to fully characterize them. This paper approaches this problem from a computational point of view. The boundary-element method is employed for analyzing the electrostatic field distribution generated by a typical arrangement, consisting of a wire-type corona electrode and an ellipse-profile nonionizing electrode. The computed results pointed out the effect of various parameters on the uniformity of the electric field near the ionizing element and at the surface of the grounded rotating roll electrode. These data can be used by the designer in order to improve the electrode configuration, produce a uniform field in the active zone of the separator, and reduce the corona inception voltage. At the same time, they validate two important premises for the mathematical modeling of the combined corona-electrostatic held of a roll-type separator: (1) Peek's law can be used for evaluating the electric field strength at the surface of the wire electrode at corona onset in any of the usual electrode configurations; and (2) the distribution of the electric field in the active zone of the separator is affected only by the geometry of the high-voltage electrode system     

高压输电线路参数对计及电晕放电的电场强度的影响

在传统模拟电荷法的基础上,建立了高压输电线路地面电场强度的计算方法,其中在计算中考虑了计及电晕放电的影响.以750 kV水平排列和紧凑型线路为例,计算了导线表面系数、线路的子导线半径、相间距、导线对地高度、分裂导线数目、分裂间距等对工频电场的影响.仿真结果表明,减小电晕放电对地面电场影响的几种方式中以适当增加导线的表面...     

有限元法分析高压架空线路附近电场分布

为准确得到实际建筑物及其周围场强分布,应用三维有限元法分析高压架空线路附近建筑物及其邻近区域中的电场分布。采用的模型考虑了高压架空线和实际建筑物(即建筑物墙壁、楼层间钢筋等)结构,并用六面体单元剖分整体模型以减少三维模型单元数量和提高计算精度。再应用子模型法校核计算结果的准确性,然后分别计算空间中有建筑物时房屋顶部和内部和无建筑物时同样位置的电场分布。最后讨论建筑物对其外部电场的畸变作用及对其内部电场的屏蔽作用。结果表明:架空线路附近的建筑物会改变空间电场分布,且建筑物附近电场强度的最大值出现在建筑物外廓尖角处。     

Computational and Experimental Study of Ionic Space Charge Generated by Combined Corona–Electrostatic Electrode Systems

Numerical computation of the electric field intensity and space charge density in electrode systems consisting of ionizing and nonionizing elements, connected at the same direct current (dc) high-voltage supply and facing a grounded plate, is a difficult problem, which is of interest to several electrostatic processes applications. The aim of the present paper is to demonstrate the effectiveness of an original method of field computation in the analysis of the factors that influence the distribution of the ionic space charge in such combined corona–electrostatic electrode systems. The computations and the experiments were carried out for an ionizing wire of diameter 0.3 mm, located at different distances$h$(10–30 mm) from a tubular support of diameter 25 mm. Several interelectrode distances (20–45 mm) were simulated. The extension of the zone at the surface of the grounded electrode, which is affected by the space charge, diminishes when reducing the intervals between these elements of the electrode system, and, at similar applied voltage, the density of the corresponding corona current increases. The experimental data were in good agreement with the computed results, validating the accuracy of the numerical method of space-charge calculation in this special electrode configuration.     

计及地电位升高的HVDC输电线路离子流场的计算

超高压直流(high voltage direct current,HVDC)输电线路离子流场的计算对于输电线路的设计具有重要意义。然而考虑地电位升高的地面离子流场的计算却很少,为此,在Deutsch假设的基础上,为了研究计及地电位升高时HVDC输电线路产生的离子流场,将地电位升高作为第1类边界条件,应用模拟电荷法,建立了考虑地电位升高影响的HVDC输电线路下方离子流场计算模型。计算结果表明,在不计及地电位下,与可查询的文献相比,计算结果与其基本一致。计及地电位下,地面离子流密度与电场的值分别有所增大,同时分析了不同地电位升高值、导线高度及极间距下,地电位的变化对超高压输电线路地面合成电场以及离子流场的影响。     

考虑接地导体时500kV开关场内的工频电场

为了深入研究变电站内工频电场在有无考虑站内电气设备接地体影响时的分布情况,推导了计算开关场内工频电场的三维模拟电荷法,以500 k V变电站为例,对变电站500 k V开关场及各类电气设备的接地体进行模型建立与工频电场分布的计算分析。首先,通过仿真结果与实测结果的对比,验证所建模型的正确性;然后分析了变电站站内有无电气设备接地体影响时的工频电场分布情况。文章方法为考虑接地体影响时站内工频电场的计算与分析提供了一种有效、快捷的途径。     

三维边界元法计算变电站空间工频电场环境*

在特高压交流变电站设计过程中,确定变电站空间电场尤其是设备附近电场的分布是相当重要的。针对变电站附近设备电场分布的复杂性,提出了三维边界元法对荆门1 000 k V变电站设备附近电场进行模拟研究,推导了三维空间合成电场极值的计算公式,并通过ANSYS仿真软件建立相应的仿真模型,对此方法进行验证,其理论计算结果与仿真结果基本一致,证明了该算法的正确性和有效性。     

1100kV GIS隔离开关的电场数值计算与分析

为了解特高压GIS隔离开关气室内部的电场强度分布情况,建立了两种典型结构的1100kV GIS隔离开关气室三维静电场数学模型。基于电场数值分析理论,采用有限元分析方法实现了大型实际工程电磁场问题的三维电场精确计算。对隔离开关的气室进行详细电场计算的结果表明,接地开关触头间隙是场强集中的区域,盆式绝缘子的结构尺寸的合理设计可以有效改善电极屏蔽罩区域的电场分布。对比两种隔离开关的电场强度分布结果可知,2种不同结构的对应区域场强最大值以及电场分布稍有差异,但都具有一定的绝缘裕度。电场分析所得的结果,为特高压隔离开关气室的整体和内部结构的进一步优化设计提供了理论依据。     

用耦合有限元方法计算高压电器电场的研究

本文将两种高阶有限单元 (高阶亚参有限单元和高阶等参有限单元 )结合在一起 ,研究了一种适用于高压电器电场计算的耦合有限元方法 ,它可进一步提高高压电器内部电场计算的准确度     

High-voltage electrode position: a key factor of electrostatic separation efficiency

Industry application of electrostatic separation technologies still faces a major difficulty: good results can be obtained only by adequate control of a multitude of operating parameters. The aim of the present paper is to analyze a key factor of electrostatic separation efficiency: the position of the high-voltage electrodes. Experiments were performed with two types of granular materials: chopped electric wire wastes and foundry sands. The electrostatic separator employed for the tests was provided with a wire-type corona electrode, associated - in some experiments - with a tubular-type electrostatic electrode, at various angular and radial positions, with respect to a rotating roll electrode connected to the ground. The experimental data are discussed in relation to the results of the numerical analysis of the electric field, carried out with a charge simulation program. They show that the outcome of the separation process (i.e., the weight percentage of the conductor and nonconductor fractions, as well as the purity of the recovered materials) depends on the configuration of the electrode system. The position of the electrodes affects both the particles charging conditions on the surface of the roll electrode, and the trajectories of the charged particles in the high-intensity electric field of the separator. Some recommendations could be formulated for the industrial application of the electrostatic separation technology.     

Calculation of high-voltage fields by means of the boundary elementmethod

Computer methods have become an essential tool for the design of high voltage equipment, in order to utilize the electric field as well as possible. The paper describes new algorithms based on the boundary element method for analyzing electric field distributions of high voltage apparatus. These algorithms regard surface elements composed of segments of realistic technical electrode and insulator surfaces. The method is illustrated by some examples from industry     

模拟电荷法计算特高压架空线路3维工频电场

为研究杆塔及导线弧垂对架空线路周围工频电场分布的影响,并检验2维计算模型的合理性与适用性,首先基于模拟电荷法建立考虑杆塔及导线弧垂的3维架空线路工频电场计算模型(它以线电荷单元为模拟电荷布置在各导线和杆塔铁棒轴线上,解析计算线电荷单元的电位系数,并叠加得到总体电位系数矩阵,从而可解得各节点的线电荷),然后据此计算了特高压线路相导线表面及地面上1m高平面内的3维工频电场。结果表明,地面上1m处平面内场强分布受弧垂影响很大,3维模型比2维模型更全面、准确地反映了这种不均匀分布状况;各相导线表面场强最大值在杆塔附近均有微弱变化,但并不显著;地面上1m处场强在杆塔附近增大,但在远离杆塔的区域基本不受杆塔影响。