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Analysis of cutting-edge techniques in the high voltage and high power adjustable speed drive systems

Science china(Technological Sciences) 2009年第2期52卷 442-449页

作者： ZHAO ZhengMing BAI Hua YUAN LiQiang State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical EngineeringTsinghua UniversityBeijing 100084China

The high voltage and high power adjustable speed drive (ASD) system is one of the most attractive fields in power electronics, and it is also a very crucial technique for energy saving and emission reduction. This paper discussed and analyzed the main cutting-edge knowledge and issues in the process of exploiting the high voltage and high power ASD system.

关键词： high voltage and high power inverter safe operation area pulse and pulse sequence

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Nanosecond-pulse Dielectric Barrier Discharge Using Magnetic Compression Solid-state Pulsed power

Nanosecond-pulse Dielectric Barrier Discharge Using Magnetic...

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IEEE International power Modulator and Hogh Voltage Conference

作者： Tao Shao Yang Yu Cheng Zhang Zheng Niu Dongdong Zhang Jue Wang Yaohong Sun Ping Yan Yuanxiang Zhou Institute of Electrical Engineering Chinese Academy of Sciences State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Electrical Engineering Department Tsinghua University

ISBN: (纸本)9781424471317

Dielectric barrier discharge excitated by unipolar pulsed power is a promising approach for producing non-thermal plasma at atmospheric pressure. A magnetic compression solid-state pulse power generator is used to produce dielectric barrier discharge (DBD). The generator is capable of providing repetitive pulses with the voltage of up to 30 kV and duration of 70 ns at a 300 Ω resistive load. This paper illustrates electrical characteristic and luminous emissions of DBD excitated by repetitive unipolar nanosecond-pulses in atmospheric air. Different from common DBD excitated by high-voltage AC sources, discharge current of DBD in the experimental investigation can be on an order of tens of amperes. When the DBD is created using two liquid electrodes, the luminous emissions from the obverse and flank sides of liquid electrodes show that no filament is observed and the discharge is homogeneous and diffuse in the whole discharge regime.

关键词： Dielectric barrier discharge Pulsed power Magnetic compression Repetitive nanosecond pulses Atmospheric pressure air Gas discharge Homogeneous discharge

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IGBT modeling for analysis of complicated multi-IGBT circuits

IGBT modeling for analysis of complicated multi-IGBT circuit...

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2009 2nd Conference on power Electronics and Intelligent Transportation System, PEITS 2009

作者： Deng, Yi Zhao, Zhengming Yuan, Liqiang State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9781424442461

A new IGBT (Insulated Gate Bipolar Transistor) model for simulation of eomplicated multi-IGBT cireuits is presented. Based on the gate chargc and discharge behaviors of IGBT, it piecewise models the turn-on and -off transient oflGBT, and simulates the static characteristics with curve fitting method . With the kcy features of high simulation spccd, easy parameters extraction and clear physical meaning, the model is available for various IGBTs and system level circuits. This paper describes the structure and equivalent circuit of the model in detail, implements it with the simulation tool of PSIM package, and determines the parameters of the model for an IGBT of FF300R12ME3 as an example. The accuracy of the model is verified by the comparison between the simulated and experimental results. ©2009 IEEE.

关键词： Equivalent circuits

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Steady-state security analysis of power system based on the operational reliability theory 3

Steady-state security analysis of power system based on the ...

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3rd International Conference on Reliability of Electrical Products and Electrical Contacts, ICREPEC 2009

作者： Zou, Xin Cheng, Lin Sun, Yuanzhang Department of Electrical Engineering State Key Lab of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing100084 China

ISBN: (纸本)9789889968489

Conventional steady-state security analysis have to compute the faults belonging to the predefined faults set in turn with out considering the small probability of the occurrence of some faults under certain circumstances. Although its results reflect the violation of the components precisely, they can not figure out how the violation affects the security of the system. The steady-state security analysis based on the operational reliability theory applies the state-depended models of the components in order to find the faults which would happen with high probability. As a result, only these faults should be calculated to decrease the computation time considerably. Further more, the reliability indices indicate the probability of the violation of the component as well as the influence of the violation on the system security, so that the security of the system can be evaluated comprehensively. IEEE RTS-79 test system is adopted in this paper to illustrate the differences between the conventional and the new steady-state security analysis methods. By contrast, it can be concluded that steady-state security analysis based on the operational reliability theory can calculate the influence of the variation of the component failure probability on the system security more specifically, which making the evaluation results more close to the practical operating system Copyright © 2009 by International Academic Publishers Ltd.

关键词： Reliability theory

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Corrigendum to “Using fuzzy theory and information entropy for water quality assessment in three Gorges region, china” [Expert systems with Applications 37 (3) (2010) 2517–2521]

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Expert systems with Applications 2010年第6期37卷 4720-4720页

作者： Li Liu Jianzhong Zhou Xueli An Yongchuan Zhang Li Yang Dispatch & Communication Center Hunan Electric Power Company Hunan Province Changsha 410007 China College of Hydroelectric and Digitalization Engineering Huazhong University of Science and Technology Hubei Province 430074 Wuhan China State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Thermal Engineering Tsinghua University Beijing 100084 China

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Shaft crack analysis and diagnosis for the 600mw steam turbine generator

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key Engineering Materials 2009年 413-414卷 591-598页

作者： Dongxiang, Jiang Liangyou, Hong Qian, Huang State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Thermal Engineering Tsinghua University Beijing 100084 China

Abstract: In order to find the cause of the shaft crack appeared in a 600MW steam turbine generator, several measurements are taken. The shaft assembly consists of three parts: shrink-fitted coupling, shaft and key which are used to transfer torque between coupling and shaft. First, the natural frequency of the shaft system is calculated. The result shows that the vibration signal contains the frequency nears the second natural frequency of the steam turbine shaft system. Second, stress field near the damaged coupling and shaft is analyzed using finite element method. The torque under different operation condition is calculated before stress analysis and applied to the shaft assembly, then. And, local stress concentrations position calculated is proved to be coincident with the place crack initiation. Finally, the cause of the fault is analyzed: at least three causes have found to be having something to do with the crack fault.

关键词： Finite element method

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state estimation based branch parameter estimation method for power grid

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2009年第1期29卷 7-13页

作者： Ning, Liao-Yi Sun, Hong-Bin Wu, Wen-Chuan Zhang, Bo-Ming State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Haidian District Beijing 100084 China

Performance of a power system security early warning and control system depends on accuracy of power grid parameter to a great extent. It is important to develop a practical branch parameter estimation method. From the results of expanded state estimation application, which is a representative parameter estimation method proposed before, it often happened that the parameters could not be estimated or estimated imprecisely. Focusing on IEEE 9 and a real-life area power grid in china, deep research on expanded state estimation method is carried out. As a result, these numerical instability and local optimization problems existing in the method were found here. A novel parameter estimation method based on Tabu search strategy is proposed to overcome these problems existing in the expanded state estimation method. Its good behavior in numerical stability and global optimization is verified by numerical tests on IEEE 9 and the real-life area power grid in china.

关键词： Global optimization

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Selection method of transformer interconnecting distributed generation and distribution networks

Selection method of transformer interconnecting distributed ...

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IEEE/PES Transmission and Distribution Conference and Exhibition: Asia and Pacific

作者： Shouzhen Zhu Lin Geng Jinghong Zheng Xiaoyu Wang DaeHee Choi Yang Li State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China

Recently, DG (distributed generation) is rapidly developed around the world. But there are several problems in the grid-connected operation. The paper focuses on the selection of proper transformers to meet the grounding requirements in the distribution networks. Through theory analysis and simulation, optimal selection methods are proposed. Yg/¿-connection transformer is suitable for small resistance grounding distribution networks while ¿ /Yg and ¿ / ¿ connection transformers are fit for small current neutral grounding networks. The conclusions are useful for the DG-connected power system.

关键词： Distributed control Grounding power transformer insulation power system simulation Coils power system interconnection Distributed power generation Ferroresonance Voltage power generation

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Research on fault mechanism of icing of wind turbine blades

Research on fault mechanism of icing of wind turbine blades

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World Non-Grid-Connected Wind power and Energy Conference, WNWEC

作者： Minghao Zhao Dongxiang Jiang Shaohua Li State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Thermal Engineering Tsinghua University Beijing China

In this paper, fault mechanism of icing of wind turbine blades is studied theoretically and experimentally. First, the aerodynamic performance of a wind turbine's primary airfoil under normal and icing conditions are simulated using Fluent software separately to analyze the geometry effect of icing on wind turbine. Then the formation and characteristics of vibration signal on main shaft caused by mass unbalance of wind turbine's rotor are analyzed using rotor dynamics theory to evaluate mass effect of icing on wind turbine. Finally, corresponding experiments are carried out on a self-made small wind turbine under laboratory conditions to testify the former theoretical analysis.

关键词： Wind turbines Blades Aerodynamics Automotive components Solid modeling Analytical models Software performance Performance analysis Geometry Shafts

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Study on modeling and simulation of non-grid-connected wind turbine

Study on modeling and simulation of non-grid-connected wind ...

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World Non-Grid-Connected Wind power and Energy Conference, WNWEC

作者： Jie Chen Dongxiang Jiang State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Thermal Engineering Tsinghua University Beijing China

In order to fully understand the characters and working principles of non-grid-connected wind turbine, this paper makes an analysis on different methods for modeling non-grid-connected wind turbine. First, according to the structure of the wind turbine, a theoretical model is presented, including three subsystems: rotor, transmission system and generator. Response of the model to a wind sequence is simulated. Then, based on the data gained from experiment, a model of small wind turbine is presented using system identification. The main content of the model is the performance coefficient Cp derived from experimental data. A comparison is made on the simulation results of the model and the data measured. With simulation results of the two methods for modeling wind turbine, by using theoretical analysis and identification respectively, we can see the two models are both effective; only that they should be applied in different conditions.

关键词： Wind turbines Wind speed Wind energy generation Rotors power system modeling power generation Wind energy Analytical models power system simulation Load modeling

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