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International Symposium on electrical Insulating Materials

作者： B. X. Du Yu Gao Lei Zhang Key Laboratory of Power System Simulation and Control of Ministry of Education School of Electrical Engineering and Automation Tianjin University TJU Tianjin China

ISBN: (纸本)9784886860057

Polybutylene terephthalate(PBT) was employed as test sample to investigate the characteristics of surface charge migration. The experiment was carried out on sample surface under a negative dc stress between two parallel electrodes. An electrostatic probe was designed to measure the surface charge density with minimum charge resolution of 0.018 pC. Obtained results show that negative charges appear near high voltage electrode, while positive charges emerge in front of grounded electrode. The hetero charges migrate towards the opposite electrode with time, forming a junction line near the grounded electrode. The polarity of surface charge tends to be positive dominated with the lapse of decay time. It is suggested that the local field at HV electrode will be seriously enhanced if the source is turned on again.

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Annual business and news:: Beginning the 31st year of the Journal of Guidance, control, and Dynamics

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JOURNAL OF GUIDANCE control AND DYNAMICS 2008年第1期31卷 1-1页

作者： Schmidt, George T. Aeronautics and Astronautics Massachusetts Institute of Technology (MIT) AIAA Institute of Electrical and Electronics Engineers Russian Federation Academy of Navigation and Motion Control Department of Mechanical and Aerospace Engineering and Engineering Mechanics University of Missouri-Rolla(UMR) Lockheed Electronics Company Center for Space Research University of Texas Austin United States Wright Laboratory Eglin Air Force Base UMR AIAA Guidance Navigation and Control Technical Committee American Automatic Control Council Lockheed Martin Aeronautics Company Palmdale CA United States C4ISR and Unmanned Air Vehicle (UAV) Programs for Air Vehicle Sciences and Systems Accreditation Board Engineering and Technology Inc./Aeronautical National Technical Committee on Guidance Navigation and Control Department of Mechanical and Aerospace Engineering University at Buffalo State University of New York (SUNY) AIAA Technical Committee on GN and C Air Vehicles Directorate Air Force Research Laboratory (AFRL) Wright-Patterson Air Force Base Space Access and Hypersonic Vehicle Guidance and Control Group Control Science Center of Excellence AFRL AIAA Technical Committee on Guidance Navigation and Control Department of Mechanical and Aeronautical Engineering University of California (UC) Davis United States Boeing Company Modernized Flight Control System for the Apache Longbow AIAA Institute of Electrical and Electronics Engineers AHS Jet Propulsion Laboratory California Institute of Technology Boeing Company Flight Sciences and Advanced Design Group Guidance Navigation and Control (GN and C) Systems Engineer Distributed Space Systems NASA Goddard Space Flight Center (GSFC) AIAA GN and C Technical Committee Department of Aerospace Engineering and Engineering Mechanics University of Texas Austin United States Institute of Navigation American Astronautical Society AIAA Guidance Navigation (GN and C) and Control Technical Committee Department of Aerospace Engineering Iowa State University Iowa

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Breakdown phenomenon identification of biodegradable polyethylene film under UV-irradiation environment

Breakdown phenomenon identification of biodegradable polyeth...

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International Symposium on electrical Insulating Materials

作者： B. X. Du Yong Liu Y. S. Xia B. C. Liu Key Laboratory of Power System Simulation and Control of Ministry of Education School of Electrical Engineering and Automation Tianjin University TJU Tianjin China Tianjin Electric Power Research Institute Tianjin China

ISBN: (纸本)9784886860057

Biodegradable polymers are increasingly expected for substitute of present insulating materials in the electrical and electronic devices. However, their electrical properties are not systematically confirmed and need further investigation. In this paper, biodegradable polyethylene (BDPE) films are employed as the specimens and high density polyethylene (HDPE) films are as the reference. The breakdown endurance of BDPE film is examined using bias DC voltage under UV-irradiation environments. The images of breakdown craters are captured through applying a monocular-video-zoom microscope. Both breakdown area and box dimension of breakdown craters are obtained by an image-pattern-identification technique. The results reveal that for both BDPE and HDPE films, the breakdown voltage, breakdown area and box dimension all decrease with the increase of UV-irradiation level. Based on comparison of the results, it shows that under UV-irradiation environment, breakdown endurance of BDPE film is better than that of HDPE film.

关键词： Electric breakdown Plastics Films Electrodes Materials Chemicals Polyethylene

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Effects of corona discharge on surface deterioration of silicone rubber insulator under reduced pressures

Effects of corona discharge on surface deterioration of sili...

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International Symposium on electrical Insulating Materials

作者： B. X. Du Yong Liu R. L. Wang Key Laboratory of Power System Simulation and Control of Ministry of Education School of Electrical Engineering and Automation Tianjin University TJU Tianjin China Tianjin High Voltage Power Supply Company Tianjin China

ISBN: (纸本)9784886860057

With the broad application of silicone rubber (SIR) insulator in high-altitude regions, corona degradation is one of the inevitable electrical degradation caused by electric stress due to the organic properties of SIR. Although this phenomenon is investigated at atmospheric pressure, there is little investigation at low pressures. It is urgent to systematically investigate effects of low pressure on the corona degradation for the reliable application. Experiments were carried out in a decompression chamber and the ambient pressure was reduced by a rotary pump from the atmospheric pressure to 40 kPa. The specimens were exposed to corona discharges at low pressures for different lapse time. The surface static contact angles on the insulator were measured to reveal the hydrophobicity changes. The currents during corona discharges at different low pressures were measured to confirm the corona degradation with variation of the pressures. The results obtained showed that the intensity of corona discharge increased with reducing the ambient pressure, which accelerated the process of corona degradation.

关键词： Corona Discharges Degradation Insulators Rubber Electrodes Aging

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Current differential protection based on Non-Conventional Instrument Transformer and IEC61850

Current differential protection based on Non-Conventional In...

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International Universities Power engineering Conference (UPEC)

作者： Kun Liu Xinzhou Dong Zhiqian Bo 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 Staffordshire 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 Synchronization IEC Phase locked loops Data communication Ethernet networks

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Study of Non-Conventional Instrument Transformer and IEC61850 impact on current differential protection

Study of Non-Conventional Instrument Transformer and IEC6185...

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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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Comparison between model based controllers for a distributed solar collector field 9

Comparison between model based controllers for a distributed...

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2007 9th European control Conference, ECC 2007

作者： Galvez-Carrillo, M. De Keyser, R. Ionescu, C. Department of Control Engineering and System Analysis Université Libre de Bruxelles Av. F.D. Roosevelt 50 - CP 165/55 BrusselsB-1050 Belgium EeSA Department of Electrical Energy Systems and Automation Ghent University Technologiepark 913 GentB-9052 Belgium

ISBN: (纸本)9783952417386

This work presents the comparison between the results obtained from applying three different control strategies for regulating the temperature in a distributed solar collector (DSC) field. A nonlinear predictive control strategy, the Nonlinear Extended Prediction Self-Adaptive control (Nonlinear EPSAC or NEPSAC), is compared with a linear predictive controller and a PI controller. All control strategies include a Smith Predictor and use a model of the process for the tuning of the controllers. Simulations on a model based on physical and geometric properties of the solar field are performed and controllers are validated on real data measurements. © 2007 EUCA.

关键词： Solar energy

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Application of a Smith Predictor based nonlinear predictive controller to a Solar Power Plant

Application of a Smith Predictor based nonlinear predictive ...

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作者： Gálvez-Carrillo, Manuel De Keyser, Robin Ionescu, Clara Department of Control Engineering and System Analysis Université Libre de Bruxelles Av. F.D. Roosevelt 50-CP165/55 B1050 Brussels Belgium Department of Electrical Energy Systems and Automation Ghent University Technologiepark 913 B9052 Gent Belgium

ISBN: (纸本)9783902661289

Renewable energies are gaining space in the energy generation panorama, thanks to technological advances and policy support. To take profit of these energies in an optimal and sustained way, research of new control strategies becomes imperative. This work presents the study and application of a nonlinear control strategy, where a Smith Predictor is added to the Nonlinear Extended Prediction Self-Adaptive control (NEPSAC), for the control of a Solar Power Plant. Different simulations are performed to study the effect of the design parameters in the dynamic behavior of the system. Copyright © 2007 IFAC.

关键词： Solar energy

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Comparison between model based controllers for a distributed solar collector field

Comparison between model based controllers for a distributed...

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European control Conference (ECC)

作者： M. Gálvez-Carrillo R. De Keyser C. Ionescu Department of Control Engineering and System Analysis Universite Libre de Bruxelles Brussels Belgium EeSA - department of Electrical energy Systems and Automation Ghent University Gent Belgium

关键词： Mathematical model Computational modeling Predictive models Feedforward neural networks Optical filters Tuning Solar radiation

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Delay-dependent Guaranteed Cost control for Uncertain Nonlinear Discrete-time systems

Delay-dependent Guaranteed Cost Control for Uncertain Nonlin...

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IEEE International Conference on Mechatronics and automation

作者： Dongmei Yue Zhiyuan Liu Xiaodong Gai Run Pei Department of Control Science and Engineering Harbin Institute of Technology Heilongjiang China Department of Equipment System And Automation Dalian Naval Academy Liaoning China Department of Electrical Engineering Harbin Institute of Technology Heilongjiang China

The delay-dependent guaranteed cost control problem is studied for a class of uncertain nonlinear discrete systems with time-delay. A sufficient condition is presented for the existence of a memory state feedback and a parameterized representation of the control laws is given in terms of certain linear matrix inequalities (LMIs). The non-convex feasible problem is converted into convex optimization problem, and the design procedure of optimal control law is given.

关键词： Costs Nonlinear control systems control systems Delay systems Sufficient conditions State feedback Linear feedback control systems Linear matrix inequalities Design optimization Optimal control

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