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Axial and radial electromagnetic-vibration characteristics of converter transformer windings under current harmonics

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High Voltage 2023年第3期8卷 477-491页

作者： Peiyu Jiang zhanlong zhang Zijian Dong Yu Yang Zhicheng Pan Jun Deng State Key Laboratory of Power Transmission Equipment&System Security and New Technology Chongqing UniversityChongqingShapingbaChina Maintenance&Test Centre EHVChina Southern Power GridGuangzhouGuangdongChina

The winding current harmonic content of converter transformer in operation is ***,affected by harmonics,the radial vibration characteristics are quite different from the power transformer,structural loosening and deformation caused by winding vibration are more ***,in view of the influence of current harmonics on axial and radial vibrations,this study builds a 3D winding electromagnetic vibration finite element simulation model,analyses the components and contents of current harmonics,compares the leakage flux and vibration distribution under the fundamental,harmonic and superimposed *** correlation relationship between the harmonic components and axial and radial vibration characteristics is obtained,and the vibration measurement test of±800 kV converter transformer in operation is carried out to verify the correctness of the analysis *** results show that the winding radial vibration amplitude will exceed the axial vibration affected by *** importantly,under the superposition of the fundamental,5th and 7th harmonic current,the vibration contribution of the converter transformer tank is mainly radial vibration,and the vibration dominant frequency is shifted from 100 Hz under the fundamental current to 400 Hz.

关键词： winding harmonics harmonic

励磁涌流引起换流变瓦斯继电器误动的振动及油流特性研究

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电工电能新技术 2024年第8期43卷 46-55页

作者：吕金壮张占龙邓军潘志城伍衡何文昊中国南方电网有限责任公司超高压输电公司电力科研院广东广州510000 输变电装备技术全国重点实验室(重庆大学) 重庆400044

在实际直流输电工程中,换流变压器在空载合闸时产生的励磁涌流导致其瓦斯继电器误动的事故频发,由于对励磁涌流下换流变压器振动及其油流特性的研究不足、故障机理不明确,瓦斯继电器误动等事故时有发生。为此,本文以某实际换流站中换流... 详细信息

在实际直流输电工程中,换流变压器在空载合闸时产生的励磁涌流导致其瓦斯继电器误动的事故频发,由于对励磁涌流下换流变压器振动及其油流特性的研究不足、故障机理不明确,瓦斯继电器误动等事故时有发生。为此,本文以某实际换流站中换流变压器网侧绕组空载合闸为例,搭建换流变压器励磁涌流电磁暂态模型,分析不同剩磁及合闸角下的换流变压器励磁涌流波形;搭建换流变压器电磁-力-流耦合的有限元模型,研究涌流作用下换流变压器的振动特性,箱体及油管内油流压强及流速特性。研究成果可为换流变压器瓦斯继电器在励磁涌流下的误动故障机理的分析提供有效参考。

关键词：换流变压器励磁涌流绕组振动油流特性

Performance Analysis of Corroded Grounding Devices with an Accurate Corrosion Model

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CSEE Journal of Power and Energy Systems 2023年第3期9卷 1235-1247页

作者： Yihua Dan zhanlong zhang Pengfei Gan Huarui Ye Qiaoyi Li Jun Deng State Key Laboratory of Power Transmission Equipment&System Security and New Technology Chongqing UniversityChongqing 400030China Test Centre of EHV Transmission Company China Southern Power GridGuangzhou 510663China

Grounding devices are significant to the operation of the power transmission line and power *** soil and leakage current can easily cause the corrosion of carbon steel grounding devices,resulting in power ***,most carbon steel grounding devices in service are already corroded,and the accurate calculation of grounding parameters for corroded grounding devices is ***,most existing methods for calculating the grounding parameters of corroded grounding devices usually have the following disadvantages:1)They only consider whether the grounding devices are broken or not,and cannot analyze the grounding parameters of grounding devices with different corrosion degrees;2)They assume that the corroded grounding device is a conductor with a smaller diameter,and ignore the impact of the corrosion product layer,resulting in calculation *** solve the above problems,this paper establishes an accurate corrosion model for grounding devices based on the volume expansion coefficient of corrosion *** grounding parameters calculation method for corroded grounding devices is proposed based on the boundary element method(BEM)and Galerkin’s *** the grounding performance of tower grounding grids with different corrosion degrees in different soils(uniform and layered)is ***,some features of grounding parameters of corroded grounding devices are *** study can accurately calculate the grounding parameters of the corroded grounding devices and has far-reaching engineering significance for the safety of power equipment.

关键词： Corroded grounding devices corrosion product layer grounding parameters volume expansion coefficient

Mode for reducing wind curtailment based on battery transportation

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Journal of Modern Power Systems and Clean Energy 2018年第6期6卷 1158-1171页

作者： zhanlong zhang Daojun MEI Han JIANG Guohua LIU Hongpeng HE Yue CHEN State Key Laboratory of Power Transmission Equipment and System Security and New Technology Chongqing University Quzhou Power Supply Company State Grid Electric Power Company

Renewable energy sources, such as wind and solar, face several obstacles, including curtailment, where the generated energy exceeds local demand and production must be reduced because of limited transmission ***, consumer demand for large-capacity batteries is expanding given the recent rapid development of electric vehicles(EVs) and plug-in hybrid EVs. A batterycharging mode, in which discharged batteries are transported from battery exchange stations in high-load areas to wind farms, is proposed to alleviate curtailment. In this study, batteries store otherwise curtailed energy and smooth the wind power output simultaneously. The structure of the battery-charging device is discussed, and the concept of a battery-charging container is proposed. The control principle of the battery-charging management unit is presented with a simulation model constructed in the PSCAD/EMTDC environment. A case study is simulated,and the feasibility of the mode is analyzed considering the levelized cost and energy losses. Simulation results show that this mode is a feasible solution to alleviating wind curtailment and providing fresh impetus for developing EV battery exchanges.

关键词： Wind curtailment Battery-charging container Transportation Power smoothing

Three-dimensional Model Analysis of Electric Field Excited by Multi-circuit Intersecting Overhead Transmission Lines

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高电压技术 2013年第8期39卷 2006-2013页

作者： XIAO Dongping LEI Hui zhang zhanlong HE Wei State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing 400030 China

This work is carried out to predict the special distribution of electric field induced by multi-circuit intersecting overhead high-voltage (HV) transmission lines (TLs) within a large range without any expensive and time-consuming computation. The two main parts of the presented methodology are 1) setting up a three-dimensional (3D) model to calculate the electric field based on combining ca- tenary equations with charge simulation method and 2) calculating the hybrid electric field excited by multi-circuit intersecting TLs using coordinate transformation and superposition technique. Examples of different TLs configurations, including a 220 kV single-circuit hori- zontally configured TLs, a 500 kV single-circuit triangularly configured TLs and a combination of the 220 kV TLs and the 550 kV TLs, are illustrated to verify the validity of this methodology. A more complicatal configurations, including a 500 kV double-circuit TLs and two 220 kV single-circuit horizontally configured TLs, are also calculated. Conclusions were drawn from the simulation: 1) The presented 3D model outperforms 2D models in describing the electric field distribution generated by practical HV TLs with sag and span. 2) Coordinate trans- formation and superposition technique considerably simplify the electric field computation for multi-circuit TLs configurations, which makes it possible to deal with complex engineering problems. 3) The electric field in the area covered by multiple intersecting overhead TLs is distorted and the hybrid electric field strength in some partial region increases so sharply that it might exceed the admissible value. 4) The configuration parameters of the TLs and the spatial configuration of multi-circuit TLs, for instance, the height of TLs, the length of span and the intersection angle of multiple circuits, influence the strength and the distribution of hybrid electric field. The influence regularities sum- marized in this paper can be referred by future TL designs t

关键词：架空输电线路电场分布模型分析相交三维多路激发 220千伏

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生物组织电导率磁感应测量原理及系统研究

仪器仪表学报 2008年第9期29卷 1878-1882页

作者：徐征何为何传红张占龙重庆大学电气工程学院输配电装备及系统安全与新技术国家重点实验室重庆400044

生物组织电导率磁感应测量是一种无接触式的测量技术,主要应用在医学磁感应成像领域。本文回顾了磁感应测量技术的发展历史及现状,指出了其研究意义。介绍了磁感应测量技术的原理,通过仿真绘出了场域内的涡流流向和涡流密度幅值分布图... 详细信息

生物组织电导率磁感应测量是一种无接触式的测量技术,主要应用在医学磁感应成像领域。本文回顾了磁感应测量技术的发展历史及现状,指出了其研究意义。介绍了磁感应测量技术的原理,通过仿真绘出了场域内的涡流流向和涡流密度幅值分布图。结果显示当场域内有异物存在时,涡流的流向会发生改变,且异物存在区域的涡流幅值明显区别于周围区域的涡流幅值。最后给出了仿真实验结果,通过模拟水槽及生物组织实验,证明通过磁感应的方法测量生物组织电导率是可行的,并指出了磁感应测量技术在医学成像领域的发展前景。

关键词：生物组织非接触磁感应测量电导率涡流

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基于一致性测度的非线性扩散图像消噪算法

光学学报 2009年第6期29卷 1530-1535页

作者：毛玉星何为张占龙重庆大学输配电装备及系统安全与新技术国家重点实验室重庆400044

以各向异性扩敞模型为基础,分析了现有扩散消噪算法在处理斑点噪声时性能不稳定和计算复杂的不足.提出了一种新的扩散方向估计算法:利用四个方向带状区域灰度的方差值作为图像的局部方向测度,引人常规与对角积分图实现方差的快速计算,... 详细信息

以各向异性扩敞模型为基础,分析了现有扩散消噪算法在处理斑点噪声时性能不稳定和计算复杂的不足.提出了一种新的扩散方向估计算法:利用四个方向带状区域灰度的方差值作为图像的局部方向测度,引人常规与对角积分图实现方差的快速计算,每个像素点的扩散量由邻域八像素与该点的差值以及相应的方向权系数决定,给出了相应的扩散函数及其计算方法。实验表明该方法适应能力强,在消除噪声同时很好地保护了纹理细节,而且迭代次数少,运算速度怏。

关键词：红外图像扩散方程消噪方差积分图

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基于微波感应技术的语音报警器

电力系统自动化 2006年第17期30卷 94-96页

作者：张占龙杨霁熊兰何亮重庆大学电气工程学院重庆市电力公司璧山供电局重庆市400078

针对电力系统中常出现的行人或电力操作人员误入电力危险区域的情形,提出了一种采用微波感应技术实现的语音警示方法,即利用微波感应传感器检测周围空间,中央处理器通过处理微波感应传感器感应信号而控制语音报警电路,从而达到对误入危... 详细信息

针对电力系统中常出现的行人或电力操作人员误入电力危险区域的情形,提出了一种采用微波感应技术实现的语音警示方法,即利用微波感应传感器检测周围空间,中央处理器通过处理微波感应传感器感应信号而控制语音报警电路,从而达到对误入危险区的人员进行语音警示的作用。文中介绍了这种语音报警器的组成、工作原理、使用范围以及推广与更新。

关键词：微波感应 PIC单片机重复录音太阳能供电

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头部电阻抗成像正问题的解析解研究

计算物理 2010年第1期27卷 107-114页

作者：徐征何为何传红张占龙重庆大学电气工程学院输配电装备及系统安全与新技术国家重点实验室重庆400044

建立头颅的球型仿真模型.用头皮、颅骨、脑脊髓和脑组织四层同心球结构模拟头颅.对各层组织采用复数电导率,用分离变量法分析头颅球模型在最外层(头皮层)表面施加点电流激励的情况下,内层的电位分布.根据电位分布的表达式,绘制出颅内的... 详细信息

建立头颅的球型仿真模型.用头皮、颅骨、脑脊髓和脑组织四层同心球结构模拟头颅.对各层组织采用复数电导率,用分离变量法分析头颅球模型在最外层(头皮层)表面施加点电流激励的情况下,内层的电位分布.根据电位分布的表达式,绘制出颅内的电位等位线图.分析电流注入角度对电位分布的影响.仿真结果表明,当颅内脑组织电导率变化时,头皮表面电位的实部变化明显大于虚部,激励电流频率变化对头皮表面电位虚部的影响较为明显.研究结果可用于分析头部电阻抗成像问题.

关键词：解析解分离变量法头部电阻抗成像