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Frequency dependent network equivalent based electromagnetic and electromechanical decoupled hybrid simulation

Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2012年第16期32卷 107-114页

作者： Zhang, Yi Wu, Wenchuan Zhang, Boming Gole, Aniruddha M. State Key Lab. of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China Department of Electrical and Computer Engineering University of Manitoba Winnipeg R3T 5V6 Canada

Neither electromechanical transient stability analysis (TSA) program nor electromagnetic transient (EMT) programs can be used individually for the transient stability studies of the large scale AC/DC systems. This paper presented an electromagnetic and electromechanical hybrid simulation system, based on a frequency dependent network equivalent. Firstly, the framework and the main modules of the proposed hybrid simulation system were introduced. Secondly, the methods to calculate the equivalents of the electromagnetic side and the electromechanical side were introduced. The discussion on the difference between the traditional method and frequency dependent network equivalent (FDNE) and the flowchart of the hybrid simulation were also given. In the last part of the paper, AC system and AC-DC hybrid system are both used as examples to demonstrate the accuracy of the proposed hybrid simulation system's simulation results. © 2012 Chinese Society for Electrical Engineering.

关键词： Hybrid systems

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Nanosecond Repetitively Pulsed Dielectric Barrier Discharge in Air at Atmospheric Pressure

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Plasma Science and Technology 2011年第5期13卷 591-595页

作者：邵涛章程牛铮于洋严萍周远翔 Institute of Electrical Engineering Chinese Academy of Sciences Key Laboratory of Power Electronics and Electric Drive Chinese Academy of Sciences State Key Laboratory of Control and Simulation of Power Systems and Generating Equipment Electrical Engineering DepartmentTsinghua University

Dielectric barrier discharge （DBD） between two cylindrical glass containers with salt water generated by a nanosecond repetitively pulsed power generator is reported. The electrical parameters, luminous images and spectrum diagnosis are presented. It is shown that the DBD possesses a large discharge current and an intense optical emission from the nitrogen second positive system below 400 nm. The gas temperature remains very close to room temperature regardless of pulse polarity. Luminous photographs with a short exposure time down to 2 ns indicate that no filament is observed and the discharge is homogeneous.

关键词： dielectric barrier discharge nanosecond pulse homogeneous discharge atmospheric pressure air emission spectrum

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Generation of Atmospheric Pressure Plasma by Repetitive Nanosecond Pulses in Air Using Water Electrodes

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Plasma Science and Technology 2011年第6期13卷 735-739页

作者：邵涛于洋章程姜慧严萍周远翔 Institute of Electrical Engineering Chinese Academy of Sciences Key Laboratory of Power Electronics and Electric Drive Chinese Academy of Sciences State Key Laboratory of Control and Simulation of Power Systems and Generating Equipment Electrical Engineering DepartmentTsinghua University

Dielectric barrier discharge （DBD） excitated by pulsed power is a promising method for producing nonthermal plasma at atmospheric pressure. Discharge characteristic in a DBD with salt water as electrodes by a home-made unipolar nanosecond-pulse power source is presented in this paper. The generator is capable of providing repetitive pulses with the voltage up to 30 kV and duration of 70 ns at a 300 Ω resistive load. Applied voltage and discharge current are measured under various experimental conditions. The DBD created between two liquid electrodes shows that the discharge is homogeneous and diffuse in the whole discharge regime, Spectra diagnosis is conducted by an optical emission spectroscopy. The air plasma has strong emission from nitrogen species below 400 nm, notably the nitrogen second positive system.

关键词： non-thermal plasma dielectric barrier discharge pulsed power nanosecondpulse pulse repetition frequency atmospheric pressure air emission spectra.

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Versatile distribution of wind power output for a given forecast value

Versatile distribution of wind power output for a given fore...

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IEEE power and Energy Society General Meeting

作者： Zhao-Sui Zhang Yuan-Zhang Sun Jin Lin Lin Cheng Guo-Jie Li State Key Laboratory of Power Systems Department of Electrical Engineering Tsinghua University Beijing 100084 China and visiting the Earth Institute Columbia University in the City of New York NY 10025 USA State Key Laboratory of Power Systems Department of Electrical Engineering Tsinghua University Beijing 100084 China Key Laboratory of Control of Power Transmission and Transformation Ministry of Education (Department of Electrical Engineering Shanghai Jiao Tong University) Shanghai 200240 China

ISBN: (纸本)9781467327275

The wind power output distribution for a given forecast value is often described by a theoretical distribution, such as Gaussian, Beta and Cauchy. However, the theoretical distributions could hardly simulate the actual wind power uncertainty for all situations. Moreover, the cumulative distribution function (CDF) or quantile function is more concerned by system operators than the probability density function (PDF). Nonetheless, the CDF of a theoretical distribution usually could not be expressed in a closed form and is commonly derived from the numerical integral of PDF. The estimation error of PDF may hence be cumulatively enlarged through the numerical integral process. Given this background, this paper presents a versatile distribution model that can simulate any shape of the actual distributions of wind power forecast errors. The CDF of the versatile distribution could be written as a closed form so it can be directly applied on fitting the actual CDF. The mathematical feature of the versatile distribution can also facilitate the dispatching decision-making and benefit power system analysis. The results demonstrate the feasibility and effectiveness of the proposed distribution model.

关键词： Cumulative distribution function (CDF) forecast probability density function (PDF) versatile distribution wind power Wind energy CAF protocol CORE DAMAGE FREQUENCY closed forms Portable document format PDF gene power output decentralised control distributed winding

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Evolution of the exploding titanium wire in 5-50 kPa ambient gas

Evolution of the exploding titanium wire in 5-50 kPa ambient...

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IEEE International Conference on Plasma Science (ICOPS)

作者： Xiaobing Zou Zhiguo Mao Xinxin Wang Weihua Jiang Department of Electrical Engineering State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China Department of Physics and Chemistry College of Physics North China University of Technology Beijing China

Experiments of electrical wire explosions (EEW) for nano-powder production were performed on a small-scale pulsed power device, which consists of a low-inductance capacitor bank of 2-4 μF typically charged to 8-25 kV. Titanium wires, 85 mm in length and 175 μm in diameter, were installed inside a discharge chamber filled with 5-50 kPa air. The peak discharge current is about 8-20kA with a rise time of 6 μs. We investigated the evolution of the exploding titanium wire with a Mach-Zehnder interferometer. From the time sequence of the interferograms, we found that two different modes of wire explosion exist, depending on the ambient gas pressure. As the gas pressure is in the range of 5-20 kPa, more than one vapor burst was observed, which we called multi-burst mode. While the gas pressure is above 40 kPa, the whole wire would explode totally within one single vapor burst, which we called one-burst mode. Based on the calculated deposition energy of the exploding wire and the gas discharge theory, we explained the relationship between the exploding modes and the ambient gas pressure.

关键词： Wires Titanium Educational institutions Discharges (electric) Physics Explosions Electrical engineering

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An Energy-based Methodology for Locating the Source of Forced Oscillations in power systems

An Energy-based Methodology for Locating the Source of Force...

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IEEE International Conference on power System Technology

作者： Li Ying Shen Chen Liu Feng State Key Lab of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing China

Recently, several power grids of China came across low frequency oscillations which are difficult to explain by the traditional negative damping mechanism. Some researchers suggest that those oscillations be caused by external periodic disturbances according to the forced oscillation mechanism. It takes no doubt that the oscillation source location (means locating the disturbances) is imperative and decisive to eliminate such a kind of oscillations. This paper proposes a location methodology based on Energy Supply on Port derived from the Port-controlled Hamiltonian theory. By calculating the energy injected to the network at corresponding ports, the oscillation sources can be effectively located, even in complicated systems containing various kinds of control devices such as governors and exciters. Different from the traditional methodology based on eigen-analysis, the proposed methodology is naturally decentralized without the dependency on global measurements. Case studies on the standard 4-machine 2-area system and the IEEE-118 bus system show the effectiveness and efficiency of the proposed methodology.

关键词： Oscillation Source Location Forced Oscillation Port-controlled Hamiltonian Energy Supply on Port

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Collision efficiency of two nanoparticles with different diameters in Brownian coagulation

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Applied Mathematics and Mechanics(English Edition) 2011年第8期32卷 1019-1028页

作者：王玉明林建忠 Institute of Fluid Measurement and Simulation China Jiliang University State Key Laboratory of Fluid Power Transmission and Control Zhejiang University

The collision efficiency of two nanoparticles with different diameters in the Brownian coagulation is investigated. The collision equations are solved to obtain the collision efficiency for the dioctyl phthalate nanoparticle with the diameter changing from 100 nm to 750 nm in the presence of the van der Waals force and the elastic deformation force. It is found that the collision efficiency decreases as a whole with the increase of both the particle diameter and the radius ratio of two particles. There exists an abrupt increase in the collision efficiency when the particle diameter is equal to 550 nm. Finally, a new expression is presented for the collision efficiency of two nanoparticles with different diameters.

关键词： nanoparticle Brownian coagulation collision efficiency different diameters van der Waals force elastic force

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IMPACT OF THE LOCATION OF DISCHARGE SOURCE ON THE PD SIGNAL IN GIS

IMPACT OF THE LOCATION OF DISCHARGE SOURCE ON THE PD SIGNAL ...

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The ⅪⅩ International Conference on Gas Discharges and Their Applications

作者： DENGWEI DING WENSHENG GAO WEIDONG LIU RUI FENG State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical EngineeringTsinghua University

ISBN: (纸本)9771003651221

In order to monitor the on-line condition of GIS and diagnose existing defects,the ultra high frequency(UHF) methods are widely used for detecting partial discharge(PD) owing to its sensitivity and anti-interference *** partial discharge will happen when the electric field is non-uniform because of the defects in *** location of the partial discharge source has an impact on electromagnetic wave generated from the *** the PD detection,the UHF signal acquired by the coupler in GIS is produced by the change in the electric field,so the characteristics of the signal are related with the position of the *** this paper,the distance between the PD source and the inner conductor of GIS is changed;the amplitude of time-domain signal and the frequency spectrum of the UHF signal are *** is discovered that the amplitude of time-domain signal is various with the distance between the defect and the inner conductor,as well as the frequency *** that, the mode of UHF signal in GIS is affected by the location of PD,the component of TEM mode and high order mode(TE mode and TM mode) change with the distance between the PD source and the inner conductor.

关键词： domain IMPACT OF THE LOCATION OF DISCHARGE SOURCE ON THE PD SIGNAL IN GIS

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Interval-parameter chance-constrained fuzzy multi-objective programming for water pollution control with sustainable wetland management

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Procedia Environmental Sciences 2012年 13卷 2316-2335页

作者： Y. Liu Y.P. Cai G.H. Huang C. Dong MOE Key Laboratory of Regional Energy Systems Optimization Sino-Canada Energy and Environmental Research Academy North China Electric Power University Beijing 102206 China CSEE University of Regina Regina Sask S4S 4H4 Canada State Key Laboratory of Water Environment Simulation School of Environment Beijing Normal University Beijing 100875 China

Water pollution control plays a significant role in the water quality management of wetland ecosystems. In this study, an interval-parameter chance-constrained fuzzy multi-objective programming (ICFMOP) model for assisting water pollution control within a sustainable wetland management system under uncertainty was developed. The proposed ICFMOP approach not only effectively handled the uncertainties and complexities in the water pollution control management systems, it also allowed decision makers to adjust the fuzzy objective control decision variable to satisfy multiple holistic and interactive objectives. The ICFMOP model developed was then applied to a wetland water pollution control case study to assist the planning of regional wetland eco-environmental sustainability. Interval solutions of the compromise decision alternatives associated with different risk levels of constraint violations were obtained. The results were helpful for decision makers to identify desirable strategies under various social-economic, environmental and system-reliability constraints with the highest system benefits and the lowest water pollutant discharge and eco-environment impact. Moreover, tradeoffs between the multiple objectives and the constraint-violation risks could be evaluated.

关键词： water quality management wetland system optimization multi-objective unceratinty

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Effects of manganese dioxide additives on the electrical characteristics of Al-doped ZnO varistors

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Science China(Technological Sciences) 2011年第8期54卷 2204-2208页

作者： LONG WangCheng HU Jun HE JinLiang LIU Jun ZENG Rong State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing 100084 China

The effects of manganese dioxide (MnO 2 ) additives on the electrical characteristics of the Al-doped ZnO varistors are investigated. The leakage current densities of the samples decrease first and then increase again with the increase of the amount of MnO 2 additives. Correspondingly, the nonlinear coefficients of the samples keep on increasing and then decrease. In addition, the donor densities increase monotonously with the amount of the doped MnO 2 increasing. The effects of MnO 2 additives on the electrical characteristics of the samples are different from the conclusion of previous literatures. The reasons of the distinct effects are supposed to be related with the donor and interface state densities of the samples.

关键词： ZnO varistots manganese dioxide electrical characteristics low residual voltage ratio simulation

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