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基于线模电流故障分量的高压直流输电线路纵联保护方案 被引量:16
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作者 戴文睿 林圣 《电力系统自动化》 EI CSCD 北大核心 2020年第19期142-149,共8页
针对现有高压直流输电线路纵联保护受分布电容影响大,动作速度慢从而导致系统闭锁这一问题,提出了一种不受分布电容影响的高压直流输电线路方向纵联保护方案。通过分析模电流传输特性得到线模电流具有受分布电容影响小的特点。基于输电... 针对现有高压直流输电线路纵联保护受分布电容影响大,动作速度慢从而导致系统闭锁这一问题,提出了一种不受分布电容影响的高压直流输电线路方向纵联保护方案。通过分析模电流传输特性得到线模电流具有受分布电容影响小的特点。基于输电线路线模阻抗推导了区内和区外故障下线路两侧测点电流幅值特征,从而利用整流侧和逆变侧测点线模电流故障分量幅值比的差异作为保护判据,构建了区内外故障识别方案,并通过理论分析为保护阈值选取提供了依据。仿真结果表明,所提保护方案能够可靠识别区内外故障,保护动作不受分布电容影响,对采样和通信要求不高,并具有较强的耐过渡电阻能力和抗噪性。 展开更多
关键词 高压直流输电 输电线 纵联保护 线模电流 故障分量
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基于故障电流特征的多端柔性直流电网故障识别
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作者 付华 张辉 《电源学报》 北大核心 2025年第5期174-184,共11页
为满足多端柔性直流电网保护的快速性和可靠性要求,提出1种基于故障电流分量的故障识别方案。方案利用故障电流行波分量的传播过程,对区内和区外故障时的电流进行分析,通过故障电流的变化差异对区内外故障进行识别;将双极线路解耦得到... 为满足多端柔性直流电网保护的快速性和可靠性要求,提出1种基于故障电流分量的故障识别方案。方案利用故障电流行波分量的传播过程,对区内和区外故障时的电流进行分析,通过故障电流的变化差异对区内外故障进行识别;将双极线路解耦得到线模分量,故障电流线模分量的极性可作方向性判据;用计算得到的正、负极故障电流的平均值之比来实现故障的选极。在PSCAD/EMTDC中建立多端柔性直流输电线路仿真模型,仿真结果表明,所提的故障识别方法无需两端通信,仅利用单端故障电流特征量就能对各种故障进行快速、准确地辨识,且具有一定的抗过电阻能力,满足柔直输电的故障保护要求。 展开更多
关键词 柔性直流输电 故障识别 故障电流 故障选极 线模电流
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基于参数辨识的柔性直流输电线路单端量保护方案 被引量:1
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作者 金恩淑 张文杰 +2 位作者 胡晓晨 杨德建 陈锦星 《高电压技术》 北大核心 2025年第2期806-815,I0022,共11页
多端柔性直流输电线路行波单端量保护存在远端经高阻接地时灵敏度较低的问题。首先,该文分析了柔性直流输电线路区内、外故障时线模电流行波的特征,根据正方向故障时电流前行波暂态能量小、反行波暂态能量大,而反方向故障时2者相反的特... 多端柔性直流输电线路行波单端量保护存在远端经高阻接地时灵敏度较低的问题。首先,该文分析了柔性直流输电线路区内、外故障时线模电流行波的特征,根据正方向故障时电流前行波暂态能量小、反行波暂态能量大,而反方向故障时2者相反的特征构建方向判据;其次,通过线路传递函数的构造,分析不同故障发生时保护安装处的故障电流首行波表达式。在此基础上,利用实测信号进行参数辨识,根据区内故障时区外行波表达式辨识不准确以及区外故障时区内行波表达式辨识不准确的特征,构造区内外故障识别判据;最后,基于正负极电流故障分量的加权比值实现故障选极。PSCAD仿真结果表明,该方案能够可靠地识别线路区内外故障,在高阻故障时具有较高灵敏度,并且具有一定的抗噪声干扰能力。 展开更多
关键词 柔性直流输电线 单端量保护 行波保护 暂态能量 参数辨识 线模电流
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一种适用于混合三端直流系统的差动保护方案 被引量:8
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作者 高淑萍 曾子璇 +2 位作者 宋国兵 段必聪 姜元月 《西安交通大学学报》 EI CAS CSCD 北大核心 2021年第1期17-26,共10页
为提高混合三端高压直流线路及母线差动保护的速动性、灵敏性、可靠性与选择性,提出一种基于Hausdorff距离算法的新型高压直流线路及母线差动保护方案。当±800 kV混合三端直流线路发生故障时,通过线模电流故障分量判定故障方向,区... 为提高混合三端高压直流线路及母线差动保护的速动性、灵敏性、可靠性与选择性,提出一种基于Hausdorff距离算法的新型高压直流线路及母线差动保护方案。当±800 kV混合三端直流线路发生故障时,通过线模电流故障分量判定故障方向,区分故障区域。对线路首末两侧电流波形进行实时短窗数据差异量化,用线路首末两端的电流相似度差异判定线路区内外故障及单双极选极。以T区送端(电网换相换流器侧)与T区两受端(模块化多电平换流器侧)电流和的Hausdorff距离差异作为T区母线故障识别保护判据。利用PSCAD建立混合三端直流输电系统模型,运用MATLAB验证所提方案。仿真结果表明:所提方案判据可耐受过渡电阻500Ω,耐受过渡电阻能力强;能在3 ms内快速可靠动作,可靠性高、快速性好;对线路两侧通信精度要求低,具有一定的抗噪和抗异常数据的能力;在不同工况下,都可快速识别故障区域及区内外故障,并实现故障选极。 展开更多
关键词 混合三端直流系统 差动保护 Hausdorff距离算法 T区 线模电流故障分量
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Numerical simulation of busbar configuration in large aluminum electrolysis cell 被引量:5
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作者 李茂 周孑民 《Journal of Central South University of Technology》 EI 2008年第2期271-275,共5页
Various busbar configurations were built and modeled by the custom code based on the commercial package ANSYS for the 500 kA aluminum electrolysis cell.The configuration parameters,such as side riser entry ratio,numbe... Various busbar configurations were built and modeled by the custom code based on the commercial package ANSYS for the 500 kA aluminum electrolysis cell.The configuration parameters,such as side riser entry ratio,number of cathode bars connected to each riser,vertical location of side cathode busbar and short side cathode busbar,distance between rows of cells in potline,the number of neighboring cells,ratio of compensation busbar carried passing under cell and its horizontal location under cell along with large magnetohydrodynamic(MHD) computation based on the custom evaluation function were simulated and discussed.The results show that a cell with riser entry ratio of 11:9:8:9:11 and cathode busbar located at the level of aluminum solution,50% upstream cathode current passing under cell for magnetic field compensation,the distance between rows of 50 m is more stable. 展开更多
关键词 numerical simulation aluminum electrolysis cell busbar configuration MAGNETOHYDRODYNAMIC
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Optimal design of auxiliary-teeth to solve circulation current reduction of permanent magnet linear synchronous motor 被引量:1
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作者 JANG Ki-bong KIM Jee-hyun +1 位作者 AN Ho-jin KIM Gyu-tak 《Journal of Central South University》 SCIE EI CAS 2011年第3期690-696,共7页
A discontinuity of magnetic circuits according to the end effect is generated in the permanent magnet linear synchronous motor (PMLSM). Due to the unbalanced back electro-motive force (EMF) and impedance produced,... A discontinuity of magnetic circuits according to the end effect is generated in the permanent magnet linear synchronous motor (PMLSM). Due to the unbalanced back electro-motive force (EMF) and impedance produced, unbalanced current is generated. The cireulatin8 current, which is caused by a decrease in the thrust, is generated by the unbalanced current. The optimal design of auxiliary-teeth at the end of the mover was carried out to solve the unbalance of phase by using design of experiment (DOE), and compared with the basic model through finite element analysis (FEA). As a result, the auxiliary-teeth model compensates for the decrease of thrust caused by the unbalanced phase. Also, this model is proven to reduce the detent force by the vibration and noise of the PMLSM and copper loss caused by the circulating current. 展开更多
关键词 permanent magnet linear synchronous motor auxiliary-teeth circulation current end effect thrust reduction
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Comparison of structure and physical fields in 400 kA aluminum reduction cells 被引量:1
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作者 丁吉林 李劼 +3 位作者 张红亮 徐宇杰 杨帅 刘业翔 《Journal of Central South University》 SCIE EI CAS 2014年第11期4097-4103,共7页
To investigate the differences and the development trends of the 400 kA aluminum reduction cell, four representative cells were deeply analyzed. By using numerical simulation methods in ANSYS software, the structure p... To investigate the differences and the development trends of the 400 kA aluminum reduction cell, four representative cells were deeply analyzed. By using numerical simulation methods in ANSYS software, the structure parameters were firstly compared, and then three-dimensional models of electric-magnetic-flow field were built and solved with finite element method(FEM). The comparison of the structures reveals that the cell bodies are similar while the current flow path and distribution ratio of bus bars are different. It appears that most of the current(70%-80%) in side A are used as the magnetic field compensation current and flow through two ends. The numerical simulation results indicate that the distributions of magnetic fields are different but all satisfy with the magnetohydrodynamics(MHD) stabilization, and the flow patterns are all two or multi vortexes with appropriate velocities. The comparison shows that all studied cells can satisfy with the physical field requirement, and the commercial applications also verify that the 400 kA cells have become the product of the mature and world's leading technology. 展开更多
关键词 aluminum electrolysis numerical simulation bus structure physical field
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