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IEEE General Meeting power& Energy Society

作者： Si-Ye Ruan Guo-Jie Li Boon-Teck Ooi Yuan-Zhang Sun State Key Laboratory of Power System Department of Electrical Engineering Tsinghua University Beijing China Department of Electrical and Computer Engineering McGill University Montreal QUE Canada

It is desirable that remote isolated communities can become self-sufficient in electric power from renewable energy sources. Renewable energy sources (wind, run of river hydro, photovoltaic) require voltage-source-converter (VSC) Stations as frequency changers to connect them to an ac grid. This paper examines the feasibility of a standalone ac grid supplied by the VSC-stations. The VSC-stations set the grid frequency and maintain real power balance of generation and load in the entire ac grid from information based on frequency deviation. Digital simulation results show the availability of a standalone ac grid supplied by the VSC-stations with proposed real power regulation.

关键词： Converters power conversion Regulators Frequency control Frequency measurement Generators Load modeling

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GPS antenna characterization in an anechoic chamber

GPS antenna characterization in an anechoic chamber

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Proceedings of the Biannual World automation Congress

作者： Nick J. LaSorte Hazem H. Refai John E. Fagan The Electrical and Computer Engineering Department University of Oklahama Tulsa OK USA State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing China The Electrical and Computer Engineering Department University of Oklahama Norman OK USA

This paper is part of a continuing work with the FAA to develop an antenna testing methodology to characterize antenna performance in a multipath environment. This paper presents a case study to determine the characterization of two GPS antennas of varying performance in real world deployment. power and phase measurements were acquired at the Wireless and Electromagnetic Compliance and Design (WECAD) Center, at the University of Oklahoma-Tulsa. Measurements were performed in a semi-anechoic chamber to characterize two broadband antennas. It is demonstrated that power and phase measurements were not sufficient to differentiate between different performing antennas in a multipath environment.

关键词： Global Positioning system Anechoic chambers Polarization Satellite broadcasting FAA Receiving antennas Performance evaluation power engineering computing power engineering and energy USA Councils

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Wavelet De-Noising for PD UHF Signals Based on Adaptive Thresholding by Genetic Algorithm

Wavelet De-Noising for PD UHF Signals Based on Adaptive Thre...

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Conference on electrical Insulation and Dielectric Phenomena, (CEIDP)

作者： Jian Li Changkui Cheng Stanislaw Grzybowski State Key Laboratory of Power Transmission Equipment & System Security and New Technology Department of High Voltage and Insulation Engineering College of Electrical Engineering Chongqing University Chongqing China High Voltage Laboratory Department of Electrical and Computer Engineering Mississippi State University MS USA

This paper presents an adaptive wavelet thresholding algorithm for de-noising of ultra-high-frequency (UHF) signals of partial discharges (PD). The wavelet de-nosing algorithm is based on an optimum and adaptive shrinkage scheme. A class of shrinkage functions with continuous derivatives and a genetic algorithm are used for the adaptive shrinkage scheme. The genetic algorithm is helpful to obtain global optimum thresholds and to reduce much time wasted by the adaptive searching computation. The de-noising results of PD UHF signals embedded in white noises are presented. The PD UHF signals denoised by the adaptive wavelet thresholding algorithm have smaller distortion in waveform than the signals de-noised by the soft thresholding algorithms.

关键词： Noise reduction Genetic algorithms Partial discharges Electrodes White noise Distortion Laboratories Dielectrics and electrical insulation Threshold voltage Frequency

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Research of the power frequency magnetic fields distribution around dry-type air-core reactor

Research of the power frequency magnetic fields distribution...

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Proceedings of the Biannual World automation Congress

作者： Zhang Yan Wang Quandi Li Bin Zhao Yi Liu Qingsheng Hazem H. Refai State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing China The Electrical and Computer Engineering Department University of Oklahama Tulsa OK USA

The strong magnetic fields generated by reactors, which not only interfere other electric equipmentspsila regularly running, but also are potentially harmful to substation employeespsila health, are the main electromagnetic contamination in substations. In this paper, a mixed finite-element (FE) model for dry-type air-core reactor, which considers the effect of eddy current, is proposed for calculation of magnetic fields. According to the analysis of this model, 7 times of the air-core reactor group region is suitable for calculation region. Based on this model, the magnetic fields distribution of equilateral triangle arranged 35 kV reactor group in 500 kV substation is calculated. The comparison between calculation results and measured values shows that the mixed FE model may accurately assess the magnetic field distribution around air-core reactors and provide theoretical basis for installation of air-core reactors for power department. Besides, based on the magnetic field distribution around air-core reactors, an early-warning mechanism can be established, which can provide safeguard for other electronic equipments running and the substation employees working.

关键词： Frequency Magnetic fields Inductors Magnetic field measurement Substations Iron Electromagnetic fields Contamination Finite element methods Eddy currents

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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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Improving Hydrophobicity of Glass Surface Using Dielectric Barrier Discharge Treatment in Atmospheric Air

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Plasma Science and Technology 2007年第5期9卷 582-586页

作者：方志邱毓昌王辉 E.KUFFEL State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong UniversityXi'an 710049China School of AutomationNanjing University of TechnologyNanjing 210009China State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong UniversityXi'an 710049China Department of Electrical and Computer Engineering University of ManitobaWinnipeg R3T 2N2Canada

Non-thermal plasmas under atmospheric pressure are of great interest in industrial applications, especially in material surface treatment. In this paper, the treatment of a glass surface for improving hydrophobicity using the non-thermal plasma generated by dielectric barrier discharge （DBD） at atmospheric pressure in ambient air is conducted, and the surface properties of the glass before and after the DBD treatment are studied by using contact angle measurement, surface resistance measurement and wet flashover voltage tests. The effects of the applied voltage and time duration of DBD on the surface modification are studied, and the optimal conditions for the treatment are obtained. It is found that a layer of hydrophobic coating is formed on the glass surface after spraying a thin layer of silicone oil and undergoing the DBD treatment, and the improvement of hydrophobicity depends on DBD voltage and treating time. It seems that there exists an optimum treating time for a certain applied voltage of DBD during the surface treatment, The test results of thermal aging and chemical aging show that the hydrophobic layer has quite stable characteristics. The interaction mechanism between the DBD plasma and the glass surface is discussed. It is concluded that CHa and large molecule radicals can react with the radicals in the glass surface to replace OH, and the hydrophobicity of the glass surface is improved accordingly.

关键词： non-thermal plasma dielectric barrier discharge （DBD） surface treatment,hydrophobicity

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Design and Implementation of an Adaptive High Impedance Fault Relay

Design and Implementation of an Adaptive High Impedance Faul...

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2007 International power engineering Conference (IPEC2007), vol.3

作者： N. Ramezani M. Sarlak S. M. Shahrtash D. Arab Khabori Department of Electrical Engineering IUST University Iran Department of Electrical Engineering Center of Excellence for Power system Operation & Automation Director of Relay Laboratory Iran University of Science and Technology Iran

To maintain both dependability and security, High Impedance Fault (HIF) relays must have a good discrimination between high impedance faults and any no-fault condition on the feeder that the relay is installed. As these types of faults exhibits very low magnitude currents, the discrimination methodologies are mostly based on the contents of current waveforms;in order to reveal any kind of distortion. Accordingly, the settings of HIF relays can not be determined by simple readings from the meters on the feeder, but they must be found through comprehensive simulations of different necessary conditions on the feeder under consideration. In this paper, an operational procedure in conjunction with a novel computational algorithm is proposed that has solved the problem of determination of HIF relays settings. The discrimination is based on the magnitude, randomness and steadiness of harmonic energy content of the current waveform. The proposed algorithm does not need any initial information from the distribution network and therefore is adaptive and treats automatically.

关键词： High Impedance Fault Relays Adaptive Protection Distribution Networks

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Temporal Analysis of power system Measurements for Condition Assessment Purposes

Temporal Analysis of Power System Measurements for Condition...

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IEEE General Meeting power& Energy Society

作者： Mirrasoul J. Mousavi Karen L. Butler-Purry ABB Inc. Raleigh NC USA Department of Electrical Engineering Power System Automation Laboratory Texas A and M University College Station TX USA

As part of the substation and feeder automation systems, various intelligent electronic devices are typically utilized to record and store digital data for protection and monitoring purposes. However, the time value of these measurements has not been paid the due attention. It is demonstrated that the information obtained from the temporal analysis of these data, online current measurements in particular, offer a unique way to prioritize resource allocation and implement a condition assessment methodology based on the incipient behavior of the system. The developed approach was successfully applied to an underground cable lateral in order to assess the severity of captured incipient abnormalities preceding the cable faults. This approach can be extended to include both overhead and underground systems at the enterprise level.

关键词： power system measurements power cables Storage automation Substation automation Intelligent systems power system protection Substation protection computerized monitoring Time measurement Data analysis

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Comparison of dielectric barrier discharge and atmospheric pressure glow discharge for surface modification of PET film

Comparison of dielectric barrier discharge and atmospheric p...

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作者： Fang, Zhi Qiu, Yuchang Kuffel, Edmund School of Automation Nanjing University of Technology Nanjing 210009 China State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong University Xi'an 710049 China Department of Electrical and Computer Engineering University of Manitoba Winnipeg R3T 2N2 Canada Nanjing University of Technology Nanjing China Xi'an Jiaotong University Xi'an China University of Manitoba Winnipeg Canada

Non-equilibrium plasmas under atmospheric pressure are of great interest in polymer surface processing because of their convenience, effectiveness and low cost. In the present work polyethylene terephthalate (PET) film surface is modified using the non-equilibrium plasma generated by the atmospheric pressure glow discharge (APGD) and dielectric barrier discharge (DBD) in ambient air. The differences in discharge characteristics between APGD and DBD are shown by measurement of their electrical discharge parameters and observation of light-emission phenomena. The effects of APGD and DBD on PET surface modification are studied by comparing their surface properties, which are characterized by contact angle measurement, X-ray photoelectron spectroscopy (XPS) and scanning electronic microscopy (SEM). It is found that the APGD is quite homogeneous and stable in the whole gas gap, which differs from the filamentary micro-discharge of the DBD. It is concluded that the APGD and DBD treatments modify the PET surface in both morphology and composition, but APGD is more effective in PET surface modification than DBD as it can modify the surface more uniformly and make the contact angle decline to a lower level.

关键词： Plastic films

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