检索结果-内蒙古大学图书馆

作者： Wang, Y. Wang, Y.T. Xu, G. Qin, M.L. Liu, S.N. Jiang, R.S. Liu, Z.D. Key Laboratory of Condition Monitoring and Control for Power Plant Equipment Ministry of Education North China Electric Power University Beijing102206 China Key Laboratory of Low-grade Energy Utilization Technologies and Systems Ministry of Education of China Chongqing University Chongqing400044 China Xinjiang Zhundong Coal Power Co. Ltd. State Grid Energy Development Company Changji831800 China

Amorphous coatings play an important role in surface modification owing to their inherent properties of high strength and abrasion resistance. A ∼4 mm thick layer of Fe based amorphous composite coating was deposited on the surface of a boiler waterwall tube by tungsten inert gas cladding. Microstructure analysis demonstrated that the coating consisted of amorphous and nanocrystallised phases. The longitudinal and transverse microhardness measurements were evaluated systematically by Vickers. The results showed that the microhardness up to 1400 HV0·3 varied under different loads and the more obvious microhardness fluctuations were observed under smaller loads. On the basis of the Hall-Petch rule, the uneven distribution of amorphous and nanocrystalline phases in the small indentation area may be responsible for the microhardness fluctuations. A careful study was undertaken of the reason for the high hardness of the coating and the microhardness fluctuation phenomenon, which may lay solid foundations for achieving a nearly three-dimensional homogeneity in the amorphous composite coating, with a large thickness. © W. S. Maney & Son Ltd. 2014.

关键词： Microhardness

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Summary of Health Index Theory and Application of state Maintenance Equipment

Summary of Health Index Theory and Application of State Main...

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The 5th International Conference on Reliability of Electrical Products and Electrical Contacts

作者： Lin CHENG Manjun LIU Feijin PENG Dept.of Elec.Eng. Tsinghua UniversityState Key Lab of Control and Simulation of Power Systems and Generation Equipments Guangdong Power Grid Company Foshan Power Supply Bureau

This paper describes several methods for condition-based maintenance,introduced CBM,RCM development process,the main theoretical logic,techniques and *** on the health index based on equipment maintenance strategies,namely *** on the development of narrative context,theoretical foundation,model healthy *** for its application in power transformers were introduced.

关键词： Health Index(HI) Condition-Based Maintenance(CBM) Reliability Centered Maintenance(RCM) Condition Based Risk Maintenance(CBRM)

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An adaptive wind power smoothing method with energy storage system

An adaptive wind power smoothing method with energy storage ...

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IEEE General Meeting power& Energy Society

作者： Hanchen Xu Can Wang Chao Lu Zhigang Lu State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China Electric Power Research Institute of China Southern Power Grid Guangzhou China

The random and intermittent nature of wind power (WP) makes the integration of large-scale wind farms into power system problematic. The energy storage system (ESS) is an effective means to smooth the WP. This paper presents a novel Kalman filter (KF) based adaptive wind power smoothing method to determine the power output of an ESS. ESS capacity can be significantly reduced by adjusting the parameters of KF adaptively according to the WP fluctuation. Meanwhile, a fuzzy logic controller is introduced to manage the remained energy level (REL) of the ESS. By considering the current WP fluctuation, the REL and the power output of the ESS together in the controller, the REL can be successfully managed to a reasonable range without deteriorating the WP fluctuation. A test case based on data from an actual wind farm validated the effectiveness of the proposed method.

关键词： Fluctuations Wind power generation Energy storage Wind farms Kalman filters Fuzzy logic Smoothing methods

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Research on HVIGBT transient mixture model and parameter extraction method

Research on HVIGBT transient mixture model and parameter ext...

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IEEE Conference and Expo Transportation Electrification Asia-Pacific (ITEC Asia-Pacific)

作者： Gaohui Feng Zhengming Zhao Liqiang Yuan Shiqi Ji Jincheng Zhao Mechanical Engineering College Shijiazhuang China State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

This paper presents a kind of HVIGBT transient mixture model and corresponding parameter extraction method. The HVIGBT model can divide into MOSFET and BJT two parts. The two models are formed respectively according to HVIGBT work principle, in addition, the carrier transport equations have been simplified for avoiding Kirk effect in BJT model. The transient model is realized in PSIM software in the paper. Extraction methods, which include estimation by empirical values, calculation by testing waveforms and comparison with same type models, are adopted in extracting model parameters. Through comparing testing and simulation waveforms, the model's simulation accuracy is proved.

关键词： Mathematical model Testing Semiconductor device modeling Transient analysis Insulated gate bipolar transistors Integrated circuit modeling Capacitance

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Study of a new grid-connected LCL filter for shunt active power filter

Study of a new grid-connected LCL filter for shunt active po...

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IEEE Conference and Expo Transportation Electrification Asia-Pacific (ITEC Asia-Pacific)

作者： Yi Wang Jian-zheng Liu Xing-Tao Xu State Key Lab of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing Beijing CN Jiangsu Electric Power Company Research Institute Nanjing China

LCL filter can improve the output current of the shunt active power filter. The paper proposes a resonant LCL filter structure with a LC high-frequency filter branches adding to LCL filter with damping resistor. By LC resonance effect, the switching frequency harmonics are filtered more efficiently and the loss of the system is reduced. The paper also builds the system modeling and analyzes the stability of the grid filter with the deadbeat control, then gives parameter selection methods and simulates with PSCAD/EMTDC. All these are verified through the experiments on a 70-KW shunt APF prototype using deadbeat controller.

关键词： power harmonic filters Damping Active filters Harmonic analysis power filters Switching frequency Resonant frequency

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Space charge behavior of XLPE/SiO2 nanocomposites with nanoparticle surface modification

Space charge behavior of XLPE/SiO2 nanocomposites with nanop...

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Electrical Insulation Conference and Electrical Manufacturing & Coil Winding Conference

作者： Ling Zhang Yuanxiang Zhou Xiaoyang Cui Yunxiao Zhang Qing Ye State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing China State Key Laboratory of New Ceramics and Fine Processing Tsinghua University Beijing China School of Electrical Engineering Beijing Jiaotong University Beijing China

ISBN: (纸本)9781479927906

Space charge behavior of XLPE/SiO 2 nanocomposites with nanoparticle surface modification via titanate(TC) and vinylsilance(VI) coupling agents was investigated. SEM results clearly show that TC and VI coupling agents improved nanoparticle dispersion within XLPE matrix due to the increasing surface hydrophobicity of SiO 2 nanoparticles. Space charge measurements under high electric field revealed that SiO 2 nanoparticles could not effectively suppress the injection and movement of space charge until organic surface modification, which was believed due to more and deeper trap sites considering the better dispersion of SiO 2 nanoparticles.

关键词： Space charge Electric breakdown Nanoparticles Nanocomposites Electric fields Surface morphology Anodes

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Analysis and simulation research on cascading trips of multiple wind farms

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Dianwang Jishu/power System Technology 2014年第6期38卷 1425-1431页

作者： Xu, Fengda Guo, Qinglai Sun, Hongbin Zhang, Boming Wang, Bin Li, Zhengshuo Ding, Tao Jia, Lin Xu, Xiaofei State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China North China Grid Company Limited Xuanwu District Beijing 100053 China

A simulation based analysis is proposed to find out the most relative factors during the cascading process, which is significant to support the future voltage control schemes for wind integration region. A hierarchical distributed simulation platform is built, which contains both the transmission and wind farms' distribution grid. In this way both the coupling among wind farms and the detailed characteristics of device level can be considered. By simulating shunt capacitors, wind turbine generators and static var compensators (SVCs) under different control mode, the different impact to cascading trips process are analyzed. With the simulation, it is found that centralized integrated wind farms are so closed-coupled that variations of active or reactive power in one wind farm would cause great changes of voltages in wind farms nearby. Researching results also indicate that coordination of various reactive power implements is essential to system voltage safety.

关键词： Wind farm

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Simplified equivalent models of large-scale wind power and their application on small-signal stability

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Journal of Modern power systems and Clean Energy 2013年第1期1卷 58-64页

作者： Nan DING Zongxiang LU Ying QIAO Yong MIN State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua UniversityBeijing 100084China

With the rapid growth of grid-connected wind power penetration level,it is necessary to study the impacts of wind power on power system *** small-signal stability of power systems with large-scale wind power is explored using the eigenvalue analysis method.A prototype sample system,the two-synchronous-generator system with a wind farm,is proposed for theoretical ***,simplified models of wind turbines(WTs)and the corresponding equivalent models of wind farms are *** kinds of typical WT models,i.e.,squirrel cage induction generator,doubly-fed induction generator,and permanent magnet synchronous generator are ***,based on the simplified equivalent models,effects of large-scale wind farms on the electromechanical oscillation modes(EOMs)of synchronous systems are *** results indicate that wind farms of the three kinds of WTs have positive effects on ***,long transmission lines connecting wind farmto the systemmay produce negative effects on the small-signal stability of the system.

关键词： Wind turbine(WT) Small-signal stability Electromechanical oscillation mode(EOM) Simplified model Equivalent model

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Modeling and analysis of unit commitment considering RCAES system

Modeling and analysis of unit commitment considering RCAES s...

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Chinese control Conference (CCC)

作者： Bin Liu Laijun Chen Yu Zhang Chen Fang Shengwei Mei Yuan Zhou State Key Lab of Control and Simulation of Power Systems and Generation Equipment Tsinghua University Beijing Beijing CN Electric Power Research Institute State Grid Shanghai Municipal Electric Power Company China Key Laboratory of Cryogenics Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing CN

Regenerative compressed air energy storage (RCAES) system is a practical and efficient solution to large-scale integration of renewable energy problems faced by power systems currently. Appropriately modeling of RCAES system is critical to its practical application, whereas research in this area has been very limited. According to the energy storage and transformation process, a concise model of RCAES system applicable to power scheduling field is proposed. Then, a unit commitment model with RCAES system is formulated as a MILP problem which can be accurately solved with high computation efficiency by CPLEX. A modified IEEE 39 bus system is used to study the impacts of parameters of RCAES system on unit commitment and the effectiveness of the proposed model is then validated. Furthermore, the proposed model can also be employed to optimize key parameters of RCAES system, e.g. efficiency and capacity of each part in an integrated way.

关键词： Energy storage Heating Computational modeling Wind power generation power grids Schedules

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Recent advances on smart grid technology and renewable energy integration

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Science China(Technological Sciences) 2013年第12期56卷 3040-3048页

作者： MEI ShengWei CHEN LaiJun State Key Lab of Control and Simulation of Power Systems and Generation Equipments (Dept. of Electrical Engineering Tsinghua University)

With the integration of renewable energy generations and other related changes,the smart grid,or the future electric power system,is confronted with new challenges and ***,it is a promising subject in electrical engineering and much work has been done on *** paper reviews the recent advances on the technologies of smart grid and renewable energy integration,from the aspects of modeling,simulation,protection and control,stability,operation,and planning.

关键词： smart grid renewable energy integration modeling simulation protection and control stability operation planning

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