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Novel Connection Scheme of Backup power Supply Adaptive to Distribution Line Non-Communication Protection and New Criterion for High Voltage and Large Capacity Induction Motor

Novel Connection Scheme of Backup Power Supply Adaptive to D...

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IEEE PES Asia-Pacific power and Energy Engineering Conference (APPEEC)

作者： Kun Liu Xinzhou Dong Zhiqian Bo State Key Lab 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

This paper presents a new practical backup power supply connection scheme for distribution line non-communication protection (DNCP). simulation tests have been conducted using the alternate transient program (ATP) with respect to a typical single circuit breaker multi-section system. The results prove that the new scheme is able to not only recover the power supply of loads on healthy lines automatically, but also create disturbances in favor of accelerated over current (AOC) criterion. Aiming at the failure of directional under voltage (DUV) criterion derived from high voltage and large capacity induction motor load, a novel criterion using the increment of reactive power is proposed.

关键词： Emergency power supplies Voltage Induction motors power system protection Circuit testing Circuit simulation system testing power system transients Circuit breakers power supplies

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Modeling of Busbars in High power Neutral Point Clamped Three-Level Inverters

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Tsinghua Science and Technology 2008年第1期13卷 91-97页

作者：易荣赵争鸣钟玉林 State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical EngineeringTsinghua University

The busbars in high power neutral point clamped three-level inverters are modeled using the Maxwell Q3D Extractor software, which is based on the partial element equivalent circuits method. The equivalent circuits of the busbars and devices model are simulated in the electric simulator PSlM to analyze the effects of the parasitic inductance on the switching characteristics of the integrated gate commutated thyristor （IGCT） in different topology positions. The simulation results agree well with the measured impedance analyzer results and the IGCT test results, which proves the effectiveness of the modeling method for the large, complex busbars.

关键词： busbars parasitic inductance partial element equivalent circuits switching characteristics

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Lightning protection study of transmission line, Part II: Analysis methods

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Gaodianya Jishu/High Voltage Engineering 2009年第12期35卷 2910-2916页

作者： Zeng, Rong He, Jin-Liang Chen, Shui-Ming State Key Lab. of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing 100084 China

Design is the key of lightning protection of transmission lines, and lightning protection analysis is the base to estimate the lightning protection behaviors of transmission line and the effect of lightning protection measures for transmission line. We mainly discussed the development states and the existed problems in lightning protection analysis of transmission line in the world, presented the analysis methods on the lightning backflash and shielding failure of transmission line and their comprehensive applications, and proposed the suitable models and methods for lightning protection analysis of transmission line. The whole-wave- progress analysis model should be applied to calculate the lightning transient characteristics of transmission line when the lightning strikes the tower or the overhead ground wires of transmission line;different analysis methods, such as electrogeometric method, the leader propagating model and the fractal model, should be used to calculate the shielding failure behaviors of transmission line. The lightning protection analysis of transmission lines should consider the micro-typological characteristics and the area difference of lightning parameters along transmission line, and comprehensively estimate the lightning protection behaviors of transmission line sections.

关键词： Electric lines

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Lightning protection study of transmission line, Part I: Lightning parameters

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Gaodianya Jishu/High Voltage Engineering 2009年第12期35卷 2903-2909页

作者： Chen, Shui-Ming He, Jin-Liang Zeng, Rong State Key Lab. of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing 100084 China

Obtaining actual lightning parameters is the fundament of lightning protection of transmission lines. Based on the comprehensive analysis on the methods to acquire lightning parameters, we analyzed the current research states and existed problems of lightning parameters, including annual lightning day, ground flash density, magnitude and waveform of lightning current. The lightning activities have obvious topographical feature, presently the lightning location system (LLS) should be fully applied to acquire the annual lightning day, ground flash density, magnitude of lightning current in different areas. Moreover, the monitoring devices of lightning current should be installed on typical transmission towers with different voltage grades in different areas to obtain the characteristics of real lightning current waveforms and magnitudes, and calibrate and check the lightning current magnitudes obtained from LLS. All these would make the lightning protection of power system focusing on the actual targets. Four sets of the developed monitoring devices of lightning current were installed, and the first lightning current waveform in China, which was similar to the standard waveform recommended by CIGRE, was recorded.

关键词： Electric lines

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Lightning protection study of transmission line, Part III: Protection measures

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Gaodianya Jishu/High Voltage Engineering 2009年第12期35卷 2917-2923页

作者： He, Jin-Liang Zeng, Rong Chen, Shui-Ming State Key Lab. of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing 100084 China

The lightning accidents threaten the safe operation of power system. We comprehensively analyzed the developing states, the existed problems in analysis methods and measures of transmission line lightning protection, and discussed the key issues of transmission line lightning protection in China that should be studied. The lightning protection measures are divided into back-up type and leading-type methods, so-called back-up type method is used in lightning protection of transmission line in China, which complicates lightning protection;but the so-called leading-type method is used in other countries, which simplifies lightning protection. The lightning protection measures for different sections of transmission lines should be comprehensively estimated and proposed by considering the micro-topographical feature and the regional performances of lightning parameters along transmission line. The lightning protection should be fully considered in transmission line design, reducing shielding angle of overhead wire, decreasing grounding resistances of tower footings, and suitably installing line surge arresters are fundamental methods of lightning protection of new transmission line.

关键词： Electric lines

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power Load Modeling Based on Wide-Area Measurements and Support Vector Machine

Power Load Modeling Based on Wide-Area Measurements and Supp...

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IEEE PES Asia-Pacific power and Energy Engineering Conference (APPEEC)

作者： Zhenshu Wang Linchuan Li Li Niu Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University TJU Tianjin China School of Electrical Engineering Shandong University Jinan China State Nuclear Electric Power Design and Research Institute Beijing China

At present, the load modeling is still one of the difficult problems in power system. In this paper, a new method is presented which uses wide-area measurements and support vector machine (SVM) for load modeling. Based on wide-area measurements, this method does non-linear regression analysis on model with SVM. By using radial basis function (RBF), model structure is optimized, and Bayesian Framework is used for identifying parameters, then a kind of non-mechanical model is founded. This method can easily solve the problems in choosing structure and identifying parameters. The founded model has good generalization ability, flexible structure, and rapid calculation speed. In the end, this method has been programmed; the simulation verifies the validity of this model.

关键词： Load modeling Wide area measurements Support vector machines power system modeling power system dynamics power system simulation control system synthesis power system measurements power system analysis computing Bayesian methods

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Instantaneous energy balancing in three-level neutral point clamped converters

Instantaneous energy balancing in three-level neutral point ...

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2008 IEEE Vehicle power and Propulsion Conference, VPPC 2008

作者： Ting, Lu Zhengming, Zhao Liqiang, Yuan Shuping, Wang State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

ISBN: (纸本)9781424418497

Instantaneous energy balancing plays an important role in power electronics conversion. The unbalance of electromagnetic energy not only debases the system performance but also decreases the reliability and efficiency of the conversion. In this paper, instantaneous energy balancing problems in three-level neutral point clamped (NPC) converters are classified and discussed. Typical examples and their usual solutions of each kind of problems are expounded and compared. In the end of this paper, limitations and disadvantages of traditional methods are analyzed, and electromagnetic field method is summarized as the new trend to analyze electromagnetic energy transmission and exchange. The method using electromagnetic field theory is emphasized to be the better approach to solve the aforementioned energy balancing problems. © 2008 IEEE.

关键词： Electromagnetic waves

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A novel modbus RTU-based communication system for adjustable speed drives

A novel modbus RTU-based communication system for adjustable...

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2008 IEEE Vehicle power and Propulsion Conference, VPPC 2008

作者： Sideng, Hu Zhengming, Zhao Yingchao, Zhang Shuping, Wang State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

ISBN: (纸本)9781424418497

The communication protocol is important for applying adjustable speed drive (ASD) systems to an industry network. This paper proposes a novel scheme of communication system for the ASD system based on Modbus protocol. The most remarkable advantage of the approach lies in the tradeoff between performance and economic cost for a power converter system. The overall system is built on master-slave structure and easy for interacting with other networks. An additional study on the cyclic redundancy check (CRC) in Modbus RTU is introduced to obtain the optimization design in the actual application and the optimization method in software design is also presented. The performance of the communication system obtained from experiment conducted on the 15kW ASD system validates the effectiveness of the proposed design method. © 2008 IEEE.

关键词： Software design

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Intelligent controller for LEDs lighting systems supplied by batteries

Intelligent controller for LEDs lighting systems supplied by...

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2008 IEEE Vehicle power and Propulsion Conference, VPPC 2008

作者： Feng, Bo Zhao, Zhengming Zhang, Yingchao Zhou, Dejia Yuan, Liqiang State Key Laboratory of Control and Simulation Department of Power System and Generation Equipment Tsinghua University Beijing China

ISBN: (纸本)9781424418497

LED lighting system supplied by batteries is one of effective solutions to vehicle and photovoltaic lighting systems. In order to improve lighting performance and prolong the life of LEDs and batteries, this paper proposes a novel intelligent controller for LED lighting systems. Stage constant current (SCC) control strategy is proposed, which determines the optimal working current of LEDs (Iref) according to their ambient temperature and the capacity of batteries. For implementing SCC control strategy, a new control algorithm of double current loops and feedforward (DCLF) control is proposed based on Boost converter with constant current source. Both output current and inductor current are used as feedback control variables and input voltage is employed as feedforward compensation in the proposed algorithm. simulations have been conducted using PSIM software;and based on that, a 50W photovoltaic LED lighting system has been developed to implement a serial of comparative experiments. The results show the advantages and validity of DCLF algorithm, such as excellent dynamic performance and good robustness. © 2008 IEEE.

关键词： Light emitting diodes

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Design and implementation of the compact main circuit of IGBT-based converter

Design and implementation of the compact main circuit of IGB...

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2008 IEEE Vehicle power and Propulsion Conference, VPPC 2008

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

ISBN: (纸本)9781424418497

The compact main circuit has many advantages, such as reducing volume and weight, saving costs and convenient for transportation. This paper presents three key problems including switching power supply, sampling and protection system, and cooling system. Through simplifying circuit and optimizing device parameters, the switching power supply can provide multiplex regulated power supplies with 540 VDC input directly. A simple circuit based on ripple principle can detect missing phase of input fault easily. The heat sink can be designed in a small volume through selecting suitable cooling fans, reducing switching frequency and setting minimum pulse width. A 15kW converter has been designed and implemented based on the above. Furthermore, this main circuit has been proved by practical application and long-term reliable operation. © 2008 IEEE.

关键词： Cooling systems

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