期刊文献+
共找到3,134篇文章
< 1 2 157 >
每页显示 20 50 100
Transient AC Overvoltage Suppression Orientated Reactive Power Control of the Wind Turbine in the LCC-HVDC Sending Grid
1
作者 Bo Pang Xiao Jin +4 位作者 Quanwang Zhang Yi Tang Kai Liao Jianwei Yang Zhengyou He 《CES Transactions on Electrical Machines and Systems》 EI CSCD 2024年第2期152-161,共10页
High-voltage direct current(HVDC) transmission is a crucial way to solve the reverse distribution of clean energy and loads. The line commutated converter-based HVDC(LCCHVDC) has become a vital structure for HVDC due ... High-voltage direct current(HVDC) transmission is a crucial way to solve the reverse distribution of clean energy and loads. The line commutated converter-based HVDC(LCCHVDC) has become a vital structure for HVDC due to its high technological maturity and economic advantages. During the DC fault of LCC-HVDC, such as commutation failure, the reactive power regulation of the AC grid always lags the DC control process, causing overvoltage in the AC sending grid, which brings off-grid risk to the wind power generation based on power electronic devices. Nevertheless, considering that wind turbine generators have fast and flexible reactive power control capability, optimizing the reactive power control of wind turbines to participate in the transient overvoltage suppression of the sending grid not only improves the operational safety at the equipment level but also enhances the voltage stability of the system. This paper firstly analyses the impact of wind turbine's reactive power on AC transient overvoltage. Then, it proposes an improved voltage-reactive power control strategy, which contains a reactive power control delay compensation and a power command optimization based on the voltage time series prediction. The delay compensation is used to reduce the contribution of the untimely reactive power of wind turbines on transient overvoltage, and the power command optimization enables wind turbines to have the ability to regulate transient overvoltage, leading to the variation of AC voltage, thus suppressing the transient overvoltage. Finally, the effectiveness and feasibility of the proposed method are verified in a ±800kV/5000MW LCC-HVDC sending grid model based on MATLAB/Simulink. 展开更多
关键词 Commutation failure LCC-HVDC Transient overvoltage Wind power
下载PDF
MEASUREMENT OF ANODIC OVERVOLTAGE BY AMODIFIED CURRENT INTERRUPTION METHOD IN CRYOLITE-ALUMINA MELTS 被引量:7
2
作者 Yang, Jianhong Lai, Yanqing +3 位作者 Xiao, Jin Li, Jie Liu, Yexiang Thonstad, J. 《中国有色金属学会会刊:英文版》 EI CSCD 1999年第1期123-129,共7页
1INTRODUCTIONIntheelectrolyticproductionofaluminium,thecelconsistsofacarbonanodeandanaluminiummetalcathode.... 1INTRODUCTIONIntheelectrolyticproductionofaluminium,thecelconsistsofacarbonanodeandanaluminiummetalcathode.Thedominantpotent... 展开更多
关键词 anodic overvoltage CURRENT INTERRUPTION METHOD aluminium electrolysis
下载PDF
Comparative study on breakdown characteristics of trigger gap and overvoltage gap in a gas pressurized closing switch 被引量:2
3
作者 Rongxiao ZHAI Tao HUANG +4 位作者 Peitian CONG Weixi LUO Zhiguo WANG Tianyang ZHANG Jiahui YIN 《Plasma Science and Technology》 SCIE EI CAS CSCD 2019年第1期87-92,共6页
Gas pressurized closing switches are one of the most important elements in FLTD-based systems. Improving the trigger performance of gas switches is useful for optimizing the output parameters and the reliability of th... Gas pressurized closing switches are one of the most important elements in FLTD-based systems. Improving the trigger performance of gas switches is useful for optimizing the output parameters and the reliability of the FLTD. In this paper, the breakdown characteristics of the trigger gap and the overvoltage gap are studied experimentally. The reasons for the different breakdown performance of the two gaps are also investigated. The results show that the breakdown delay of the trigger gap is more influenced by the trigger voltage, while the breakdown delay of the overvoltage gap is more influenced by the working coefficient and always higher than that of the trigger gap. The jitter of the trigger gap is more influenced by the trigger voltage and accounts more than 60% of the total switch jitter, while the jitter of the overvoltage gap is hardly changed with the trigger voltage as well as the working coefficient and maintains less than 1.4 ns. It is proved that the discharging product from the trigger gap can effectively reduce the breakdown delay and jitter of the overvoltage gap. Based on that, the effect and improvement of pre-ionization on the two gaps are also studied. It is concluded that the jitter of the trigger gap reduces obviously when the pre-ionization is added, while the pre-ionization almost has no effect on the jitter of the overvoltage gap. The jitter of the overvoltage gap is about two times higher than the trigger gap in the pre-ionizing switch. 展开更多
关键词 gas SWITCH breakdown characteristic pre-ionization TRIGGER GAP overvoltage GAP
下载PDF
STUDY OF ANODIC OVERVOLTAGE IN NEODYMIUM ELECTROLYSIS 被引量:1
4
作者 K.R. Liu, J.S. Chen, Q. Han and X.J. WeiSchool of Materials and Metallurgy, Northeastern University, Shenyang 110004, China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2003年第5期355-359,共5页
The anodic overvoltage of neodymium electrolysis was determined by slow scanning oscillograrn. The effects of some factors, i.e. the temperature, the anodic current density, the concentration of Nd2O3 and the componen... The anodic overvoltage of neodymium electrolysis was determined by slow scanning oscillograrn. The effects of some factors, i.e. the temperature, the anodic current density, the concentration of Nd2O3 and the components of the electrolyte were investigated and the approaches to decrease the anodic overvoltage were also discussed. The results show that the anodic overvoltage increases with the anodic current density and decreases with the increasing temperature. The linear relation between the anodic overvoltage and the current density corresponding to Tafel equation is determined to some extent. The anodic overvoltage decreases with the increasing concentrations of LiF and NdF3. It also decreases by controlling the anodic current density properly, increasing the temperature or the concentrations of LiF and NdF3 and the reducing polar distance. 展开更多
关键词 neodymium electrolysis anodic overvoltage deposition voltage FLUORIDE
下载PDF
Overvoltage and Insulation Coordination for Valve Winding of ±800 kV UHVDC Converter Transformer 被引量:5
5
作者 ZHOU Peihong DAI Ming HE Huiwen 《高电压技术》 EI CAS CSCD 北大核心 2012年第12期3146-3155,共10页
关键词 直流换流变压器 绝缘配合 过电压 特高压 转阀 绕组 绝缘水平 直流输电工程
下载PDF
Overvoltage and Insulation Coordination of Jinping-Sunan ±800 kV UHVDC Porject Converter Stations 被引量:2
6
作者 YU Shifeng NIE Dingzhen MA Weimin TONG Yuliang 《高电压技术》 EI CAS CSCD 北大核心 2012年第12期3219-3223,共5页
关键词 过电压保护 绝缘配合 特高压直流输电 换流站 苏南 高压直流输电系统 高压直流输电工程 设备制造
下载PDF
Overvoltage Identification in Distribution Networks Based on Support Vector Machine 被引量:2
7
作者 DU Lin DAI Bin +2 位作者 SIMA Wen-xia LEI Jing CHEN Ming 《高电压技术》 EI CAS CSCD 北大核心 2009年第3期521-526,共6页
关键词 电压在线监测系统 电压波形 支持向量机 计算方法 供电技术
下载PDF
Transfer Function Based Recognition of Resonance Overvoltages Transformer Windings 被引量:1
8
作者 M. Florkowski J. Furgal 《高电压技术》 EI CAS CSCD 北大核心 2008年第12期2558-2563,共6页
Power transformer insulation systems are subjected to many stresses during normal operation due to lightning and switching.If the spectrum of incoming surge voltage matches the winding one,the corresponding resonance ... Power transformer insulation systems are subjected to many stresses during normal operation due to lightning and switching.If the spectrum of incoming surge voltage matches the winding one,the corresponding resonance will be excited.Therefore external transients occurring in power systems might trigger internal overvoltages with large maximum value in transformer windings.Overvoltages having such characteristic have been the root cause of many power transformer failures.The paper presents an approach to the identification of sensitive zones in the transformer windings based on the measurements of overvoltages inside windings and frequency dependences of admittance of the power transformer.The frequency characteristic of the transformer winding may determine those regions in the frequency spectrum.The presented approach might be used both for design optimization and diagnostics of distribution and power transformers. 展开更多
关键词 变压器 绕组 谐振 过电压识别 传输函数
下载PDF
Modeling of Nonlinear Elements During Lightning Overvoltage Simulations 被引量:3
9
作者 J. Bajorek M. Korzeniowski G. Maslowski R. Ziemba 《高电压技术》 EI CAS CSCD 北大核心 2008年第12期2595-2601,共7页
The paper presents some problems of lightning overvoltage modeling in transmission lines with nonlinear elements.The presented results were obtained mostly for fast front transients of subsequent lightning return stro... The paper presents some problems of lightning overvoltage modeling in transmission lines with nonlinear elements.The presented results were obtained mostly for fast front transients of subsequent lightning return stroke currents.The effectiveness of numerical algorithms of nonlinear models and possibilities of their development for such transients are analyzed.Computer simulations carried out by application of EMTP show that nonlinear models of back-flashover and ZnO arresters work properly,while the implemented corona model can not be used for relatively large peak values of subsequent lightning return-stroke currents. 展开更多
关键词 雷电过电压 仿真 非线性无件 模型
下载PDF
Overvoltage Condition Assessment of a Microgrid Due to Faults Occurring in the Islanded Mode of Operation
10
作者 Ricardo Leon Vasquez-Arnez Dorel Soares Ramos Tesoro Elena Del Carpio Huayllas 《Energy and Power Engineering》 2015年第11期525-534,共10页
This paper presents the results of the simulations and their respective analyses corresponding to the power frequency overvoltages resulting from various fault types occurring inside a microgrid. During the islanded m... This paper presents the results of the simulations and their respective analyses corresponding to the power frequency overvoltages resulting from various fault types occurring inside a microgrid. During the islanded mode of operation, the analysed microgrid can be simultaneously fed by a diesel generator, a 1 MW wind power turbine, a small solar system and a 1 MW hydroelectric scheme. The operating voltage of the microgrid is 2.4 kV. During a fault in the system, the overvoltages normally occur in two remarkable instants. The first one occurs at the beginning of the fault itself. The second one occurs at the instant when the fault is cleared. The major concern here is the overvoltage during the fault period. Due to the travelling wave effect along cables and overhead lines composing the microgrid system, these overvoltages can be amplified, thus jeopardizing the insulation level of the microgrid transmission system and related equipment. Much of the work available now is dedicated to overvoltages present in high-voltage systems leaving a gap for the study and behaviour on low voltage microgrid systems. The overvoltage stress is characterized by the maximum low-frequency, short-duration (crest value) of the overvoltage. Both cables and overhead lines that constitute the microgrid transmission system are characterized by their R-L-C parameters. The simulations of the microgrid system are conducted using the ATP program. According to the international ANSI and IEEE standards, the minimum BIL (Basic Impulse Insulation Level) and BSL (Basic Impulse Switching Level) for the 2.4 kV voltage level are 20 kV and 10 kV, respectively;thus, care should be taken so that the healthy phases upon which commonly appear such overvoltages are not exceeded in their insulation level. 展开更多
关键词 Islanded MODE MICROGRIDS overvoltage SHORT-CIRCUIT
下载PDF
Analysis on the Effect of the Nonlinear Resistance on the Locomotive Operating Overvoltages
11
作者 Zhengqing Han Donglin Zhang +1 位作者 Yuning Wu Shibin Gao 《Energy and Power Engineering》 2013年第4期1243-1248,共6页
With the application of the articulated phase insulator, and the speed of electric locomotive rising, it is inevitable for the electric locomotive to adopt the technology automatic passing through the electric phase s... With the application of the articulated phase insulator, and the speed of electric locomotive rising, it is inevitable for the electric locomotive to adopt the technology automatic passing through the electric phase separation. However, when the locomotive passes the electric phase separation, a variety of overvoltages will be generated, such as the cut-off overvoltage and the closing overvoltage. In this paper, the causes of the two overvoltages above are analyzed theoretically and simulated in Simulink. Then this paper discusses the suppression effects on the cut-off overvoltage and the closing overvoltage by paralleling the nonlinear resistance and the main breaker, or parallelling the nonlinear resistance and the locomotive transformer. The simulation results show that parallelling the nonlinear resistance and the locomotive transformer has suppressive effects on the two overvoltages mentioned above. 展开更多
关键词 ARTICULATED Phase INSULATOR Switching overvoltage Nonlinear Resistance SIMULINK
下载PDF
The Research of Voltage Sag and Power Frequency Overvoltage on 110kV Resistance Grounding System
12
作者 Guo Zeng Guangliang Feng +1 位作者 Yanping Lv Shan Sun 《Energy and Power Engineering》 2013年第4期873-876,共4页
This paper researches the voltage transfer characteristics when one-phase ground fault occurred in the resistance grounding system, by using the theory of the asymmetric variable characteristics and the sequence netwo... This paper researches the voltage transfer characteristics when one-phase ground fault occurred in the resistance grounding system, by using the theory of the asymmetric variable characteristics and the sequence network analysis of the -11 transformer, and concludes the scope of voltage sag and swell and the degree of power frequency overvoltage and their influencing factors in the 110 kV resistance grounding system. Accordingly this paper puts forward the resistance choosing principle: the resistance grounding coefficient must be equal to or greater than 10. So it can not only wipe out the voltage sag and voltage swell but also make sure the overvoltage is limited to electrical equipment allowing range. The method mentioned above is verified by simulation results of a 110 kV power system in ATP. 展开更多
关键词 NEUTRAL GROUNDING System by RESISTANCE One-phase GROUNDING FAULT Power Frequency overvoltage
下载PDF
Research on Mechanism of Overcurrent and Overvoltage When Contactless Tap Changer Switch Regulates Voltage on Load
13
作者 ZHAOYu-lin DONGShou-tian +2 位作者 LIJia-hui NIJing YUEHong-bin 《Journal of Northeast Agricultural University(English Edition)》 CAS 2003年第1期60-65,共6页
Analyzes the mechanism of overvoltage when contactless tap changer switch which is applied in distributing transformer converted directly.When the device convert the tap off,it employs the way that the SSR is switche... Analyzes the mechanism of overvoltage when contactless tap changer switch which is applied in distributing transformer converted directly.When the device convert the tap off,it employs the way that the SSR is switched on when voltage through zero and switched off when current through zero.But in the experiment we found that overvoltage will occur in the process of changing tap changer.The paper illustrates the mechanism of overvoltage in theory by analyzing the equivalent circuit and using analytic method of transition process. 展开更多
关键词 load ratio control tap joint switch solid state relay overvoltage MECHANISM
下载PDF
Relevant Factors to a Statistical Analysis of Overvoltages - Application to Three-Phase Reclosing of Compensated Transmission Lines
14
作者 P. Mestas M.C. Tavares 《Energy and Power Engineering》 2013年第4期1165-1171,共7页
This paper describes the statistical study of important factors that influences transient over voltages resulting from three-phase reclosing of shunt compensated transmission lines. These factors include the model use... This paper describes the statistical study of important factors that influences transient over voltages resulting from three-phase reclosing of shunt compensated transmission lines. These factors include the model used for transmission line representation and the influence of line transposition. Additionally, the over voltages reduction to proper levels depending on the type of control technique are illustrated and analyzed in statistical terms. The evaluation covers three shunt compensation degrees. The digital simulations were performed using the PSCAD/EMTDC software. 展开更多
关键词 Transient overvoltageS THREE-PHASE RECLOSING Controlled Switching SURGE ARRESTERS Pre-insertion Re-sistor
下载PDF
Lightning Overvoltages on Rural Distribution Lines 被引量:1
15
作者 A. Piantini D. M. Duarte F. Romero 《高电压技术》 EI CAS CSCD 北大核心 2008年第12期2564-2569,共6页
This paper presents information concerning the characteristics of lightning overvoltages on overhead power distribution lines.Discussion on the protection measures against transients caused by both direct and indirect... This paper presents information concerning the characteristics of lightning overvoltages on overhead power distribution lines.Discussion on the protection measures against transients caused by both direct and indirect strokes is also presented. 展开更多
关键词 农村 配电线路 雷电过电压保护 间接雷击
下载PDF
Overvoltage Suppression for UHV Transmission Lines
16
作者 李永丽 刘太华 +3 位作者 李仲青 景雷 龙英 范建忠 《Transactions of Tianjin University》 EI CAS 2008年第3期222-225,共4页
The overvoltage phenomena of ultra high voltage (UHV) transmission lines are analyzed and verified by EMTDC/PSCAD simulation. Referring to the theoretical analyses and operating experiences of extra high voltage (EHV)... The overvoltage phenomena of ultra high voltage (UHV) transmission lines are analyzed and verified by EMTDC/PSCAD simulation. Referring to the theoretical analyses and operating experiences of extra high voltage (EHV) transmission lines in China and UHV transmission lines in Russia and Japan, the methods to suppress the internal overvoltage in UHV transmission lines by protection and control strategies are discussed. Through the cooperation among the recloser, shunt reactor, tripping and closing resistance, and metal oxide varistor(MOV), the overvoltage can be restrained within an acceptable level. 展开更多
关键词 overvoltage RECLOSING relay protection shunt reactors SUPPRESSION UHV transmission lines
下载PDF
Analysis of Switching Overvoltage in Regional Grid with Small Hydropower Plants
17
作者 Juan Chen Haifeng Li 《Engineering(科研)》 2013年第9期19-23,共5页
Present-day small hydropower plants (SHPs) have a large development potential because of the increasing interest in renewable resources and distributed energy generation, therefore, there are many SHPs in places of Ch... Present-day small hydropower plants (SHPs) have a large development potential because of the increasing interest in renewable resources and distributed energy generation, therefore, there are many SHPs in places of China where are rich in water resources. However, it has caused overvoltages in the distribution network, and which is even worse for the switching overvoltage such as isolated network operation, changing power supply path. The simple network model is used to analyze the reasons of the switching overvoltage, and the simulation software DIgSILENT/PowerFactory is used to check out the results of the theoretical analysis. 展开更多
关键词 Small HYDROPOWER ISOLATED Operation CHANGING Power Supply PATH Switching overvoltage
下载PDF
Calculation and Analysis of Switching Overvoltage Front Time and Switching Impulse Insulation Coordination for UHV AC Transmission Line of Chinese Pilot Project and Double-circuit Project 被引量:2
18
作者 ZHOU Peihong HE Huiwen 《高电压技术》 EI CAS CSCD 北大核心 2014年第6期1781-1794,共14页
关键词 特高压交流输电 交流输电线路 中国国家标准 操作过电压 软件计算 时间脉冲 试点项目 绝缘配合
下载PDF
Protection of ±500 kV HVDC Double-circuit Converter Station from Lightning Induced Overvoltage 被引量:1
19
作者 DONG Manling YUAN Zhiyong +3 位作者 LI Tianwei ZHAO Xiangen ZHANG Jiaxin HE Junjia 《高电压技术》 EI CAS CSCD 北大核心 2013年第8期2053-2060,共8页
In order to obtain reasonable schemes of arrester in converter stations, the arrester scheme of "Xiluodu-Guangdong HVDC ± 500 kV double circuit transmission" project against lighting induced overvoltage... In order to obtain reasonable schemes of arrester in converter stations, the arrester scheme of "Xiluodu-Guangdong HVDC ± 500 kV double circuit transmission" project against lighting induced overvoltage, which was designed according to the main principle of lightning protection in converter station, is discussed. A calculation of the lighting induced overvoltage in Zhaotong converter station un- der various operation modes is performed with ATP-EMTP software, then the surge arrester configuration of the converter station is decided, and the arrester protection schemes of smoothing reactor and neutral line are studied. It is concluded that additional protection is necessary because of the relatively large gap between protected disconnecting switch and arrester of metallic return transfer bus. Plus, the smoothing reactor (SR) arrester near the valve hall could be removed to improve the scheme’s economic performance. 展开更多
关键词 高压直流输电 过电压保护 换流站 双回路 雷电感应 ATP-EMTP 平波电抗器 避雷器
下载PDF
Determination of ohmic/voltage drop and factors influencing anodic overvoltage of carbon anodes in Na_3AlF_6-Al_2O_3 based melts
20
作者 李庆余 李劼 +1 位作者 田忠良 张刚 《中国有色金属学会会刊:英文版》 EI CSCD 2003年第3期699-703,共5页
Experimental technique has been inadequate to anodic overvoltage measurements in aluminum electrolysis. To determine its ohmic/voltage drop precisely, a current interruption technique was modified with a high frequenc... Experimental technique has been inadequate to anodic overvoltage measurements in aluminum electrolysis. To determine its ohmic/voltage drop precisely, a current interruption technique was modified with a high frequency digital oscilloscope, current interrupters with fast switching time, an improved cell configuration and a simulation applied to the oscillating potential decay curve. The results show that the technique can give good reproducibility for overvoltage studies. A substantial increase of anodic overvoltage is observed with graphite powder addition, metallic aluminum addition and CO bubbling in the melts. 展开更多
关键词 炼铝 碳阳极 电解 阳极过电压 Na3AlF6-Al2O3 滴定分析 一氧化碳
下载PDF
上一页 1 2 157 下一页 到第
使用帮助 返回顶部