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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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Research on performance robustness of PID control for TITO process with time delays

Research on performance robustness of PID control for TITO p...

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The 8th World Congress on Intelligent control and Automation(第八届智能控制与自动化世界大会 WCICA 2010)

作者： Zengrong Hu Jing Wang Donghai Li Weiqi Li Metallurgical Engineering Research institute　University of Science & Technology Beijing China　Scho Metallurgical Engineering Research institute University of Science & Technology Beijing China State Key Lab of Power Systems Dept of Thermal　Engineering Tsinghua University Beijing China Department of automatic control，School of Automation Beijing Institute of Technology，Beijing ，China

PID controller has simple structure and easy applicability with strong performance robustness. Decentralized PID controller and decoupling PID controller are widely adopted in the control of two-input-two-output (TITO) processes. Firstly, a simple decoupling controller matrix and a desired dynamic decoupling controller matrix are designed according to the idea of coupling matrix. And then three schemes of controller including decentralized PID controller, simple PID decoupling controller and desired dynamic PID decoupling controller are provided based on the excellent characteristic of DDE. Lastly, the Monte-Carlo stochastic experiment is introduced to analyze performance robustness of the controllers. The simulation experiments illustrate that the simple decoupling control scheme has the ability of complete decoupling and better performance robustness.

关键词： Robustness Mathematical model Distributed control Equations Delay effects Process control

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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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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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2009 Asia-Pacific power and Energy Engineering Conference, APPEEC 2009

作者： Liu, Kun Dong, Xinzhou Bo, Zhiqian State Key Lab of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China AREVA T and D Automation Stafford ST17 4LX United Kingdom

ISBN: (纸本)9781424424870

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. © 2009 IEEE.

关键词： Induction motors

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Performance of negative sequence pilot protection applications in transmission line with open-phase operation

Performance of negative sequence pilot protection applicatio...

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

作者： Bin Wang Xinzhou Dong Zhiqian Bo Andrew Klimek State Key Lab of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China AREVA T and D UK Limited Stafford UK

ISBN: (纸本)9781424452293

The performance of the negative sequence pilot protection (NSPP) is less deteriorated by the phase-ground shunt capacitance since the negative sequence current loops in phase-phase lines. Hence NSPP is a good candidate for the main protection in UHV lines with the special characteristic of larger charging current. But as we all known, NSPP is not suit to the open-phase operations in transmission line, which limited its wide applications in HV/EHV lines in history. In response to this question, the performance of NSPP in transmission line with open-phase operation is analyzed, and the mal-operation reason of the NSPP relay is discovered. Then an improved algorithm for faults detection is proposed in open-phase line, and the simulation results verified its validity. The work in this paper is only the basic steps, the more research, such as the sensitivity and transient characteristics of ground fault detections in open-phase line should be discussed further.

关键词： Protection Transmission lines Capacitance Fault detection Voltage control power system simulation power system transients History Performance analysis Relays

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Effect of frequency on electrical tree characteristics in silicone rubber

Effect of frequency on electrical tree characteristics in si...

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International Conference on Properties and Applications of Properties and Applications of Dielectric Materials

作者： Qiong Nie Yuanxiang Zhou Zhengzheng Chen Haihang Chen State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept of Electrical Engineering Tsinghua University Beijing 100084 China Dept of Electrical Engineering Zhengzhou University 450001 China

As an advanced internal insulating material, silicone rubber has been widely used in extra high voltage prefabricated cable accessories. However, few studies were focused on the influence of frequency on the electrical tree characteristics and the damage mechanism of such insulation is still unknown. In this paper, the characteristics of electrical tree in silicone rubber under AC voltage of different frequency ranging from 50 Hz to 130 kHz were studied. The tree initiation voltage was measured at room-temperature and the processes of electrical tree were observed via a digital micro-observing system. From the experiments, it was found that the electrical tree in silicone rubber is greatly affected by the frequency of applied voltage. With the increase of frequency, tree initiation voltage of silicone rubber decreases. And the frequency can be separated into four stages, while tree initiation voltage appears different magnitude of decrease. There are 3 kinds of electrical tree during the experiments: branch tree, trunk tree and pine tree. The branch tree and pine tree are the primary shapes in the range of low frequency, while the bush tree is the primary shape in the range of HF. The dielectric spectroscopy of silicone rubber was also measured. At last, the influence of frequency on electrical tree in silicone rubber was analyzed. The repeated electro-mechanical stresses applied to the needle tip under high frequency may lead to the decrease of tree initiation voltage of silicone rubber. And with the increase of frequency, the serious erosion in silicone rubber by electrical tree may be caused by the great increase of dielectric losses.

关键词： Frequency Rubber Trees - insulation Shape measurement Dielectric losses Cable insulation Dielectrics and electrical insulation Voltage measurement Electric variables measurement Hafnium

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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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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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