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IEEE/PES Transmission and Distribution Conference and Exposition: Latin America

作者： K. L. S. Shenxing X. Dong Z. Bo State Key Lab of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China Tsinghua University Beijing Beijing CN State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China AREVA T&D Automation슠and Information Systems Stafford UK

Non conventional instrument transformer (NCIT) and IEC 61850 are crucial technologies in digital substations. But they bring some new uncertainties to protection IEDs, especially the time synchronization issue in current differential protection. The paper analyzes the time delay of transferring sampled values from NCIT to current differential relay in NCIT and IEC61850 based digital substation, then finds out the delay-non-deterministic problem, at last presents a novel current differential protection scheme by using phase-locked loops (PLL ) technology.

关键词： Substations Delay effects Ethernet networks Phase locked loops IEC Synchronization Data communication

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Preparation of TiO films by cathode multi arc ion and its performance

Preparation of TiO films by cathode multi arc ion and its pe...

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International Nano-Optoelectronic Workshop, iNOW

作者： Duojin, Fan Duowang, Fan Chenglong, Wang Lingxiao, Ming Lin, Zhao Hongzhong, Liu Lanzhou Dachen Automatic Control System Co. Ltd. Lanzhou 730070 China MOE Key Lab. of Opto-electronic Technology and Intelligence Control Lanzhou Jiaotong University Lanzhou 730070 China State Key Laboratory for Manufacturing Systems Engineering Xi'an Jiaotong University Xi'an 710049 China

TiO films were prepared by custom-made Cathode Multi Arc Ion equipment. Experimental test results reveal that our equipment can easly deposite big area scale TIO, particle size is in nanometer scale. © 2007 IEEE.

ISBN: (纸本)1424415918

关键词： Particle size

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Short-term Reliability Online Evaluation Basing On Transient State Probability

Short-term Reliability Online Evaluation Basing On Transient...

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IEEE General Meeting Power& Energy Society

作者： Lin Cheng Haitao Liu Xin Zou Yuanzhang Sun Electrical Engineering Department at Tsinghua University Electrical Engineering School State Key Lab of Power System Control and Simulation Tsinghua University

The reliability of the power system in a future short term is studied according to the current state. Basing on this, we can alarm and prevent the outage to assure the safety and reliability of the power system. Traditional reliability is an expected value of long-term reliability level under the fixed operating mode, which cannot reflect the real time reliability level under the current operational state. This essay presents the novel conception and algorithm of online evaluating the short-term reliability in order to study the operational reliability level. The influence of the variable system states on the reliability level is reflected according to the real time operational information provided by the SCADA/EMS/WAMS. Markov process is adopted to solve the transient state probability of the components, so that forecasting the system state basing on the transient probability is possible. The probability of the system state and the reliability indices of the system changes as the time varying. The analysis and the assessment of IEEE RTS-79 system indicates that there are great differences between the short-term and long-term reliability indices, and only the transient probability evaluation can assess the short-term probability properly. In this paper the relationship between the enumerating number of the system states and the forecasting time is also studied. The result indicates that only a few system states are needed to get relative high degree of evaluation accuracy, which can be applied online. IEEE RTS-79 case study is calculated to verify this conclusion.

关键词： Power system reliability Power system transients Power system security Markov processes Real time systems Steady-state Reliability theory Safety Medical services Time varying systems

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Synthesis and photocatalytic capability of Cr-TiO2 film

Synthesis and photocatalytic capability of Cr-TiO2 film

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International Nano-Optoelectronic Workshop, iNOW

作者： Xiaojuan, Lu Duowang, Fan Duojin, Fan Hongzhong, Liu School of Automation and Electric Engineering Lanzhou Jiaotong University Lanzhou 730070 China MOE Key Lab. of Opto-electronic Technology and Intelligence Controll Lanzhou Jiaotong University Lanzhou 730070 China Lanzhou Dachen Automatic Control System Co. Ltd. Lanzhou 730070 China State Key Laboratory for Manufacturing Systems Engineering Xi'an Jiaotong University Xi'an 710049 China

A TiO2 catalyst doped by Cr was prepared by the sol-gel method and characterized by UV-2550 and FS. The results revealed that the Cr 6+-doped TiO2 film had the higher photocatalytic activity than pure TiO2 film. ©... 详细信息

ISBN: (纸本)1424415918

关键词： Sol-gel process

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Preparation of TiO films by Cathode Multi Arc Ion and its Performance

Preparation of TiO films by Cathode Multi Arc Ion and its Pe...

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International Nano-Optoelectronics Workshop (i-NOW)

作者： Duojin Fan Duowang Fan Chenglong Wang Lingxiao Ming Lin Zhao Hongzhong Liu Lanzhou Dachen Automatic Control System Company Limited Lanzhou China MOE key lab of Opto-electronic Technology and Intelligence Control Lanzhou Jiaotong University Lanzhou China State Key Laboratory for Manufacturing Systems Engineering Xi'an Jiaotong University Xi'an China

关键词： Cathodes Coatings Scanning electron microscopy Optical films X-ray scattering Substrates Vacuum technology Materials science and technology Automatic control control systems

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Synthesis and Photocatalytic Capability of Cr- TiO2 film

Synthesis and Photocatalytic Capability of Cr- TiO2 film

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2007年纳米光电子学国际学术会议

作者： Xiaojuan Lu Duowang Fan Duojin Fan Hongzhong Liu School of Automation and Electric Engineering Lanzhou Jiaotong University Lanzhou 730070 People's MOE key lab of Opto-electronic Technology and Intelligence Controll Lanzhou Jiaotong University La Lanzhou Dachen Automatic Control System Co. Ltd Lanzhou 730070 and People's Republic of China State Key Laboratory for Manufacturing Systems Engineering Xi'an Jiaotong university Xi'an 710049

A TiO2 catalyst doped by Cr was prepared by the sol-gel method and characterized by UV-2550 and FS. The results reveal that the Cr6+-doped TiO2 film has the higher photocatalytic activity than pure TiO2 *** Semiconductor photocatalysts, mainly TiO2, have attracted much attention in last decade because of their potential application in the removal of many organic and inorganic pollutants in air or water. Many studies have been carried out on the application and modification of TiO2, and various photocatalytic reactors have been investigated according to respective application demands for the purification of air and water. In the water and wastewater treatment field, slurry reactor is the most common device because of its high specific surface area and good dispersion. However, the use of TiO2 slurry reactor is still limited mainly due to difficult separation of TiO2 particles from treated water. To overcome the problem, Titania beads, TiO2 based thin film, fiberglass loaded with titania, and encapsulated titania within a zeolite framework have been prepared and used in fixed bed. However, the activity of TiO2 photocatalyst is reduced to a considerable extent by these immobilization techniques because the effective surface area of photocatalysts is decreased considerably. The aim of this study is to obtain a magnetically separable photocatalyst, which is stable and easy to be prepared. In the work, Cr as magnetic cores was prepared by liquid catalytic phase transfer method at low temperature, and magnetically separable TiO2- Cr photocatalysts were synthesized. Their physicochemical properties and photocatalytic activity for degradation of methyl orange in water were investigated.

关键词： Chromium Water pollution Inductors Semiconductor films Wastewater treatment Slurries Magnetic separation Air pollution Purification Surface treatment

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Sensitivity analysis for AC/DC hybrid power systems

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Dianli Xitong Zidonghua/Automation of Electric Power systems 2007年第12期31卷 45-49页

作者： Liu, Chongru Zhang, Boming Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control North China Electric Power University Beijing 102206 China State Key Lab. of Power Systems Department of Electrical Engineering Tsinghua University Beijing 100084 China

The interactions between AC and DC systems in the steady-state condition of power systems are investigated. Through a sensitivity analysis, the influence of DC control parameters on the operation of AC/DC systems and that of AC control parameters on other AC parameters with the DC system existing are discussed. The sensitivity matrices and the influence factors between AC and DC systems are analyzed from various points of view. The sensitivity analysis made in this paper is expected to be of practical significance in such problems as load flow control, parameter regulation, voltage estimation, etc.

关键词： Electric power transmission networks

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EEG signal analysis based on time-variant coupled network Lattice model

EEG signal analysis based on time-variant coupled network La...

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ICBPE 2006 - 2006 International Conference on Biomedical and Pharmaceutical engineering

作者： Minfen, Shen Guoliang, Chang Shuwang, Wang Beadle, Patch J. Key Lab. of Digital Signal and Image Processing of Guangdong Province Shantou University Shantou China School of System Engineering Portsmouth University Portsmouth United Kingdom

ISBN: (纸本)8190426249

Brain electrical activity is widely accepted as the typical non-stationary signal. In addition, there exist more evidences that both EEG and ERP signals are chaotic signal produced by the nonlinear dynamics system. To investigate the time-varying nonlinear dynamics of the ERP under specified cognitive tasks, a novel model based on the time-variant coupled map lattice system is proposed for this purpose. The time-variant largest Lyapunov exponent (LLE) is also defined as the quantitative parameters to reveal the global characters of system and discover new information. Several simulations and real ERP signals under different fixed location cue were examined in terms of LLE spectra for studying the signal's dynamic complexity. The experimental results show that the brain chaos changes with time under different attention tasks of the information processing. The influence of the LLE with the scopes size of cues mainly occurs in P2 period. No simple linearly relationship between the scopes of cues and the influence of complexity is found. © 2006 Research Publishing Services.

关键词： Dynamics

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Power Losses for IGCTs and Diodes in MV Three-level Inverters

Power Losses for IGCTs and Diodes in MV Three-level Inverter...

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International Conference on Power Electronics and Drive systems (PEDS)

作者： Yuan Liqiang Zhao Zhengming Yang Zhi Department of Electrical Engineering State Key Lab of Control and Simulation of Power System Tsinghua University Beijing China Department of Frequency-converter and Control System GuoDian NanJing Automation Company Limited Nanjing China

The power-loss models for different switching states of IGCTs and diodes in MV (medium voltage) three-level NPC (neutral point clamped) inverters are presented in this paper. The models, simulation implementation and the revisional experiments on IGCT test platform are described in details. The relation between the power losses and the other elements of the inverter is analyzed and discussed.

关键词： Diodes Switches Pulse width modulation inverters Power system modeling Medium voltage Variable speed drives Circuits Cooling Pulse width modulation Snubbers

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Study on the method of restraining the ending effect of empirical mode decomposition (EMD)

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Beijing Ligong Daxue Xuebao/Transaction of Beijing Institute of Technology 2006年第3期26卷 196-200页

作者： Xu, Bao-Jie Zhang, Jian-Min Xu, Xiaoli Li, Jian-Wei School of Mechanical and Vehicular Engineering Beijing Institute of Technology Beijing 100081 China Measurement and Control of Mechanical and Electrical System Key Lab. of Beijing Beijing Institute of Machinery Beijing 100085 China

Ending effect is produced in the decomposition process of empirical mode decomposition (EMD) based Hilbert-Huang transformation. It leads to distortion near the two end points of the signal processed. Several methods of restraint aimed at ending effect are proposed. Comparison has been made among the global average statistic method, the parallel line extending method, the polynomial curvefitting method, the mirror extending method and the neural networks extending method. As a result of simulation and experiment, it is shown that ending effect can be effectively restrained.

关键词： Signal theory

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