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2011 IEEE Energy Conversion Congress and Exposition (ECCE 2011)

作者： Fanbo He Zhengming Zhao Liqiang Yuan Sizhao Lu State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9781457705427;9781457705410

A fast DC-link voltage controller is desirable to reduce the DC-link capacitor for PV inverters. This paper proposes a method for single-phase grid-connected PV inverters to remove the ripple component from the DC-link voltage signal and a scheme to regulate the DC-link voltage based on energy-balance analysis. The proposed scheme provides excellent dynamic performance as well as a function to prevent DC-link overvoltage by limiting the input power, which is verified by both simulation and experiments.

关键词： DC link Polydnaviridae dc-link capacitor Inventors Voltage regulators dynamic characteristics DC link voltage Scheme Voltage regulation link voltage

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Voltage Fluctuation Suppression Method of Floating Capacitors in a New Modular Multilevel Converter

Voltage Fluctuation Suppression Method of Floating Capacitor...

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2011 IEEE Energy Conversion Congress and Exposition (ECCE 2011)

作者： Kui Wang Yongdong Li Zedong Zheng Lie Xu State Key Laboratory of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China

ISBN: (纸本)9781457705427

Modular multilevel converter (MMC) is a newly emerging multilevel topology for high power applications in recent years. The voltage fluctuation problem of a new MMC topology is studied in this paper. In order to suppress the voltage fluctuation of the floating capacitors, a control method is proposed by injecting high frequency zero-sequence voltage and phase-to-phase circulating currents. It can be used to drive an induction motor with pump/blower-like load at low speed and improve the performance significantly. A low power three-phase five-level prototype is built up to validate this method.

关键词： Bridge circuits Fluctuations Capacitors Voltage fluctuations Voltage control Frequency modulation Time frequency analysis

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An approach to determining the local boundaries of voltage stability region with wind farms in power injection space

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Science China(Technological Sciences) 2010年第12期53卷 3232-3240页

作者： MU YunFei & JIA HongJie key laboratory of power system simulation and control of Ministry of Education, Tianjin University, Tianjin 300072, China 1. Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University Tianjin 300072 China

A new approach to determining the local boundaries of voltage stability region in power injection space (IVSR) for power system with wind farms is presented. It can be used for power system voltage stability analysis and on-line security assessment with considering the output uncertainty of the wind farms. Firstly, power flow tracing and double dispatching are used to determine the generators that are closely related to the wind farms, in order to balance the power fluctuations caused by the wind speed variation. Then, modal analysis is used to get the key generators to achieve an effective dimension reduction for IVSR. Finally, the forecasting output power (or wind speed) of wind farms is divided into several intervals. For each interval, the corresponding local IVSR boundaries can be calculated by the method based on small disturbance. Moreover, parallel process is used to accelerate the computing speed. The presented approach is validated by several power systems. It can be revealed that the approach can give the local IVSR boundaries at different wind speeds and has a good engineering application prospect.

关键词： voltage stability region power flow tracing modal analysis parallel process

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Model predictive control for vehicle emergency motion planning based-on flatness

Model predictive control for vehicle emergency motion planni...

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作者： Cong, Yanfeng Chen, Hong Sawodny, Oliver Yu, Zaitao Guo, Shuai State Key Laboratory of Automobile Dynamic Simulation Changchun 130025 China Institute for System Dynamics Stuttgart 70511 Germany Department of Control Science and Engineering Jilin University Changchun 130025 China

ISBN: (纸本)9789881725592

In this paper, we consider the vehicle online motion planning for the avoidance of emergency situations under structured environment as the object of our researching. In the framework of MPC, a motion planning method based on flatness is proposed. Based upon the descriptions and definitions of structured environment, trajectory planning algorithms and strategy are presented. In order to satisfy feasibility and safety, vehicle dynamics constraints are taken into account. The simulation results illustrate that the effect is satisfying. © 2011 Chinese Assoc of Automati.

关键词： Motion planning

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A Generalized Leakage Inductance-Based Method for Discrimination of Internal Faults from Inrush Currents

A Generalized Leakage Inductance-Based Method for Discrimina...

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IEEE power and Energy Society General Meeting

作者： Jing Ma Tong Wang Jie Wu Zengping Wang School of Electrical and Electronic Engineering North China Electric Power University Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control under Ministry of Education North China Electric Power University State Nuclear Electric Power Planning Design and Research Institute

ISBN: (纸本)9781457710001

A novel scheme based on generalized leakage inductance (GLI) to distinguish the inrush current from the internal fault current in the power transformer is proposed. By eliminating the mutual flux linkage in the transformer loop equation and adopting the trapezoid principle, the GLI is calculated in the real time. According to the difference between the GLI and the leakage inductance obtained from transformer manufacturer, the criterion to identify the internal fault is developed. A total of 162 experimental cases have been tested and the proposed method is able to reliably and accurately discriminate internal faults from inrush currents with easy implementation. Also, the method is suitable if it is not possible to measure the currents in the delta winding. Furthermore, the method is independent of the B-H curve and iron losses.

关键词： Generalized leakage inductance Inrush current Internal fault current power transformer Inrush current internal fault ELECTRIC TRANSFORMERS currents INFLUX ocean currents water currents magnetization curve fault currents Extravasation Transformer Core loss

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Energy cost and greenhouse gas emissions of a Chinese solar tower power plant

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Procedia Environmental Sciences 2011年 5卷 77-80页

作者： Q. Yang G.Q. Chen Y.H. Zhao B. Chen Z. Li Z.F. Wang State Key Laboratory of Turbulence and Complex Systems College of Engineering Peking University Beijing 100871 China China Hua Dian Corporation Beijing 100035 China State Key Joint Laboratory of Environmental Simulation and Pollution Control School of Environment Beijing Normal University Beijing 100875 China Key Laboratory of Solar Thermal Energy and Photovoltaic System of Chinese Academy of Sciences Institute of Electrical Engineering P.O. Box 2703 Beijing 100190 China

It is commonly assumed that the application of solar power system can save energy and relief global climate change. Presented in this study is the account of energy performance and greenhouse gas emissions of a planned solar tower power plant in China based on the life cycle analysis method. The conservative estimation of energy cost for the concerned plant is 1.21 times of the electricity output, which is a relatively decent performance amongst power generation technologies. In order to analyze the greenhouse gas performance, a comparison is carried out between the solar tower power plant and conventional coal-fired power plant in China. Results show the application of this solar system obtains a net greenhouse gas emission reduction of 0.31E+06 ton CO2 equivalent, during its operating period of twenty years. It is believed that this successful example can lend solid support to a future wide use of solar power in China.

关键词： Solar tower power plant Electricity generation Energy analysis Greenhouse gas emission

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Surface Breakdown of Printed Circuit Board under Magnetic Field with Reduced Pressure

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Transactions of Tianjin University 2010年第1期16卷 6-10页

作者：杜伯学朱晓辉高宇卢欣 Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University Tianjin Electrical Power Science Research Institute

Epoxy resin laminate onto which a pair of copper foil was printed was employed as test *** samples were placed in an artificial atmospheric chamber, which was vacuumed by a rotary pump from 100 kPa to 5 *** magnetic field was produced by permanent magnets that were assembled to make E×B drift away from, into and parallel to the sample surface, *** flux density was adjusted at 120 mT, 180 mT and 240 mT *** applying a negative bias voltage between the electrodes, the ...

关键词： printed circuit board surface breakdown magnetic field ambient pressure

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Transient interaction of HVAC and HVDC in converterer station in HVDC, I: Electromagnetic transient model of equipments in DC side

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Gaodianya Jishu/High Voltage Engineering 2011年第2期37卷 395-403页

作者： Chen, Shui-Ming Yu, Zhan-Qing Xie, Hai-Bin Huang, Lu-Lu State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China

Huge interconnected power grids are formed in AC and DC power systems in China. The nanoseconds, microseconds, milliseconds electromagnetic transient due to AC and DC system operation and fault, the DC converter valve movement, the load generated by changes interact in the AC and DC interconnected system, impairing AC and DC power systems, especially leading to the commutation of DC system failures and atresia such serious incidents. Consequently, a theoretical analysis was combined with a test method to establish an over ground network, considering DC electrical networks, control systems and underground grounding system of the full-wave process of the UHV system, Finally, converter transformer was modeled with UMEC model, and transmission line was modeled with J-Marti frequency dependent model;moreover, valve was modeled with transistor, RLC circuit, and other units including DC controller, and DC filter and AC filter were modeled with RLC circuit. The broadband characteristics of electromagnetic transient models of key units in DC sides for the analysis of AC and DC interconnected system were also analyzed.

关键词： controllers

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Transient interaction of HVAC and HVDC in converter station in HVDC, IV: Effects of DC sides on AC sides

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Gaodianya Jishu/High Voltage Engineering 2011年第7期37卷 1590-1597页

作者： Chen, Shui-Ming Yu, Zhan-Qing Huang, Lu-Lu Xie, Hai-Bin State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China

China AC-DC power systems are interconnected to form a huge power grid. The nanoseconds, microseconds, milliseconds electromagnetic transient were generated due to AC-DC system operation and fault, the DC converter valve movement, the load generated by changes in the interaction of AC-DC interconnected system electromagnetic transient, which can pose a hazard on AC and DC power systems, in particular, can lead to the commutation of DC system failures and atresia such serious incidents. Based on the broadband characteristics model which can accurately reflect the existing AC-DC interconnected system electromagnetic transient characteristics of the key components, we applied the PSCAD/EMTDC platform to establish a computational model, and revealed DC side electromagnetic transient interaction on AC side. The results show that the DC system has little effect on AC system electromagnetic transient, In various types of failures, the overvoltage produced at side of 750 kV, 330 kV lines and bus are in the allowable range.

关键词： HVDC power transmission

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Effect of Different Arresters on Switching Overvoltages in UHV Transmission Lines

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Tsinghua Science and Technology 2010年第3期15卷 325-328页

作者：杨鹏程陈水明何金良 State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical EngineeringTsinghua University

The amplitude of switching overvoltages is a key factor for designing the insulation of UHV equipment. The effect of different arresters needs to be studied, since installing arresters is an important way to suppress switching overvoltages in UHV transmission lines. Switching overvoltages on the 1000 kV Huainan-Huxi double-circuit transmission line were simulated for different operating modes and different arrester designs using the electromagnetic transient program PSCAD/EMTDC. With parallel resistors, the switching overvoltages are less than 1.70 p.u. （1.0 p.u.=1100×√ 2 /√3 kV）. If the arrestors are better, the switching overvoltages can be reduced even lower to 1.55 p.u. Without parallel resistors, the arresters can reduce three-phase energizing overvoltages to 1.70 p.u, while the single-phase reclosing overvoltages still exceed the limit. The results show that the parallel resistors cannot be eliminated if the arresters are only installed at each end of the transmission line. Also, better quality arresters significantly lower the switching overvoltages.

关键词： UHV double-circuit transmission line switching overvoltages arresters

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