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Repeated Strike Process During Disconnector Operation in Ultra-High Voltage Gas-Insulated Switchgear

Plasma Science and Technology 2016年第3期18卷 247-253页

作者：关永刚蔡元纪陈维江刘卫东李志兵岳功昌张俊民 State Key Lab of Control and Simulation of Power System and Generation Equipments Department of Electrical EngineeringTsinghua UniversityBeijing 100084China State Grid Corporation of China Beijing 100031China China Electric Power Research Institute Beijing 100192China School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China

Very fast transient over-voltage （VFTO）, induced by disconnector operations in gas- insulated switchgears, has become the limiting dielectric stress at ultra-high voltage levels. Much work has been done to investigate single-strike waveforms of VFTO. However, little study has been carried out investigating the repeated strike process, which would influence VFTO significantly. In this paper, we carried out 450 effective experiments in an ultra-high voltage test circuit, and conducted calculations through the Monte Carlo simulation method, to investigate the repeated strike process. Firstly, the mechanism of the repeated strike process is proposed, based on the ex- perimentai results. Afterwards, statistical breakdown characteristics of disconnectors are obtained and analyzed. Finally, simulations of the repeated strike process are conducted, which indicate that the dielectric strength recovery speed and polarity effect factor have a joint effect on VFTO. This study enhances the understanding of the nature of VFTO, and may help to optimize the disconnector designed to minimize VFTO.

关键词： disconnector （DS） repeated strike process discharge statistical breakdowncharacteristics ultra-high voltage （UHV） very fast transient over-voltage （VFTO）

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Linear Precoding Design for MIMO-PLC Systems

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Tsinghua Science and Technology 2015年第2期20卷 155-163页

作者： Jisheng Peng the State Key Lab of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua Uinversity

In this paper, we consider the design of linear precoding in Multiple Input Multiple Output （MIMO） Power Line Communication （PLC） systems with finite-alphabet input. First, we derive mutual information of MIMO-PLC systems with impulsive noise. Considering the non-concavity of the objective function and the low-cost requirement of PLC systems, we choose the lower bound of the mutual information as the objective function. Subsequently, we propose a novel approach to design the precoding scheme to reduce computational complexity. Specifically, our work primarily includes the following two contributions：（1） We design the right unitary matrix that is a product of two fixed unitary matrices, which only depends on the modulation mode. Hence, the results can be saved and require less computations. （2） For the power allocation matrix, we first reduce the space of power allocation using constraints of the optimal power allocation policy. Consequently, we propose a non-linear search method to obtain the optimal power allocation in small space. In regards to the computational complexity of the analysis, we conclude that the proposed precoding matrix design scheme has low complexity and is easy to implement. Moreover, the numerical results are proven to demonstrate the performance of the proposed precoding design scheme.

关键词： precoding design MIMO-PLC impulsive noise finite-alphabet input

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Author Correction: Near-real-time monitoring of global CO2 emissions reveals the effects of the COVID-19 pandemic

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Nature communications 2020年第1期11卷 6292页

作者： Zhu Liu Philippe Ciais Zhu Deng Ruixue Lei Steven J Davis Sha Feng Bo Zheng Duo Cui Xinyu Dou Biqing Zhu Rui Guo Piyu Ke Taochun Sun Chenxi Lu Pan He Yuan Wang Xu Yue Yilong Wang Yadong Lei Hao Zhou Zhaonan Cai Yuhui Wu Runtao Guo Tingxuan Han Jinjun Xue Olivier Boucher Eulalie Boucher Frédéric Chevallier Katsumasa Tanaka Yiming Wei Haiwang Zhong Chongqing Kang Ning Zhang Bin Chen Fengming Xi Miaomiao Liu François-Marie Bréon Yonglong Lu Qiang Zhang Dabo Guan Peng Gong Daniel M Kammen Kebin He Hans Joachim Schellnhuber Department of Earth System Science Tsinghua University Beijing China. zhuliu@***. Laboratoire des Sciences du Climat et de l'Environnement LSCE CEA CNRS UVSQ Centre d'Etudes Orme de Merisiers Gif-sur-Yvette France. Department of Earth System Science Tsinghua University Beijing China. Department of Meteorology and Atmospheric Science The Pennsylvania State University University Park PA USA. Department of Earth System Science University of California Irvine 3232Croul Hall Irvine CA USA. Division of Geological and Planetary Sciences California Institute of Technology Pasadena CA USA. Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA. Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Collaborative Innovation Center of Atmospheric Environment and Equipment Technology School of Environmental Science and Engineering Nanjing University of Information Science and Technology Nanjing China. Key Laboratory of Land Surface Pattern and Simulation Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China. Climate Change Research Center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China. Key Laboratory of Middle Atmosphere and Global Environment Observation Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China. School of Environment Tsinghua University Beijing China. School of Mathematical School Tsinghua University Beijing China. Department of Mathematical Sciences Tsinghua University Beijing China. Center of Hubei Cooperative Innovation for Emissions Trading System Wuhan China. Faculty of Management and Economics Kunming University of Science and Technology 13 Kunming China. Economic Research Centre of Nagoya University Furo-cho Chikusa-ku Nagoya Japan. Institut Pierre-Simon Laplace Sorbonne Université/CNRS Paris France. Université Paris Dauphine Place du Maréchal de Lattre de Tassigny 75016 Paris France.

A Correction to this paper has been published: https://***/10.1038/s41467-020-20254-5.

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Electrical tree initiation and propagation in silicone rubber under long-term AC aging

Electrical tree initiation and propagation in silicone rubbe...

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2016 IEEE Conference on Electrical Insulation and Dielectric Phenomena, CEIDP 2016

作者： Zhang, Yunxiao Zhou, Yuanxiang Zhang, Ling Ming, Chen Zhang, Xu Yanchao, Sha State Key Lab of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing100084 China North China Electric Power Research Institute Co Ltd. Beijing100045 China

ISBN: (纸本)9781509046546

Electrical tree break-down is the major failure problem in cable accessories, however, mechanisms of the electrical tree initiation and propagation are still lack of deeply research, especially in silicone rubber (SIR) which is widely used as insulation material for cable accessories. Long-term aging (0- 1000 h) experiments under the different voltages were conducted to observe electrical tree initiation and propagation processes. In trees initiation stage, with increasing of applied voltage, electrical tree initiation probability becomes larger, while tree initiation time dramatically decreases. The experiment observations demonstrated four shapes of trees which are dominated. As applied voltage increasing, the numbers of electrical trees life-cycles increased and exponential relationship was found between tree length and magnitude of applied voltage. It is noted that charges, whose energy exceeding a certain critical value, destroy microstructure of dielectric accumulatively via injection and extraction, and cause electrical trees initiate when it accumulates to a visible extent. © 2016 IEEE.

关键词： Life cycle

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Diesel Engine SCR control: Current Development and Future Challenges

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Emission control Science and Technology 2015年第2期1卷 121-133页

作者： Yuan, Xinmei Liu, Hongqi Gao, Ying State Key Lab. of Automotive Simulation and Control Jilin University ChangchunJilin130025 China

To meet increasingly stringent emission legislations, selective catalytic reduction (SCR) becomes an essential aftertreatment technique. This paper presents a comprehensive overview of the current development and future challenges of SCR control technologies. In this paper, SCR system hardware configurations are introduced, modeling and calibration of the SCR converter are provided, and current control strategies are summarized and reviewed. Finally, primary areas driving the future of SCR control research are discussed. © 2015, Springer SIP, AG.

关键词： Selective catalytic reduction

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Analysis of Fault Characteristics of Half-wavelength AC Transmission Lines

Analysis of Fault Characteristics of Half-wavelength AC Tran...

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IEEE Power and Energy Society General Meeting

作者： Teng Feng Xinzhou Dong Bin Wang Shenxing Shi Shuxin Luo Aoyu Lei Lanxi Tang State Key Lab. of Control and Simulation of Power System and Generation Equipment Dept. of Electrical Engineering Tsinghua University

ISBN: (纸本)9781509041695

Half-wavelength AC transmission (HWACT) is an ultra-long distance AC transmission technology, whose electrical distance is close to half-wavelength at the system power frequency. The countries with a large territory have a big demand for HWACT. The fault characteristics of an HWACT line can be different from those of a conventional transmission line. So it is necessary and significant to analyze the fault characteristics of an HWACT line. In this paper, the influence of fault distances and fault resistances on the fault voltages and currents of two buses is analyzed after different types of faults occur on an HWACT line. And the analysis results are compared with the simulation results from EMTP.

关键词： Fault characteristics Fault distance Fault resistance Fault type Half-wavelength AC transmission fault resistance half-wave AC power transmission faults electrical distance power frequency Electromagnetic Transients Program fault signature Analysis

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Development of low cost hardware-in-the-loop test system and a case study for electric vehicle controller

Development of low cost hardware-in-the-loop test system and...

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International Conference on Applied System Innovation (ICASI)

作者： Jing Lin Xia Qinghua Diao Wei Sun Zengzhen Xing Xinmei Yuan Tingting Dong State Key Lab.of Automotive Simulation and Control Jilin University Changchun Jilin China Geely Automobile Institute Hangzhou Zhejiang China

ISBN: (纸本)9781467398893

In recent years, hardware-in-the-loop (HIL) test becomes an effective approach in the design of automotive electronics. One issue of HIL system is that most commercial HIL products are very expensive. With careful analysis of the ECU functionality and reasonable use of the hardware resources, it is possible to realize a HIL system to fully satisfy the test requirements with much lower cost in many cases. In this paper, the possibilities to reduce the cost of current HIL systems are discussed. As a case study, the development of a low cost HIL system for a pure electric vehicle controller is presented, the modeling of the vehicle is introduced and the hardware and software implementations are given. Finally, the feasibility of the proposed HIL system is validated by experimental results.

关键词： Decision support systems control systems Industrial electronics

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Repeated Strike Process During Disconnector Operation in Ultra-High Voltage Gas-Insulated Switchgear

Repeated Strike Process During Disconnector Operation in Ult...

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作者： Guan, Yonggang Cai, Yuanji Chen, Weijiang Liu, Weidong Li, Zhibing Yue, Gongchang Zhang, Junmin State Key Lab of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing100084 China State Grid Corporation of China Beijing100031 China China Electric Power Research Institute Beijing100192 China School of Automation Science and Electrical Engineering Beihang University Beijing100191 China

Very fast transient over-voltage (VFTO), induced by disconnector operations in gas-insulated switchgears, has become the limiting dielectric stress at ultra-high voltage levels. Much work has been done to investigate single-strike waveforms of VFTO. However, little study has been carried out investigating the repeated strike process, which would influence VFTO significantly. In this paper, we carried out 450 effective experiments in an ultra-high voltage test circuit, and conducted calculations through the Monte Carlo simulation method, to investigate the repeated strike process. Firstly, the mechanism of the repeated strike process is proposed, based on the experimental results. Afterwards, statistical breakdown characteristics of disconnectors are obtained and analyzed. Finally, simulations of the repeated strike process are conducted, which indicate that the dielectric strength recovery speed and polarity effect factor have a joint effect on VFTO. This study enhances the understanding of the nature of VFTO, and may help to optimize the disconnector designed to minimize VFTO.

关键词： Monte Carlo methods

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High impedance fault detection on distribution systems with harmonic interference in wind farms

High impedance fault detection on distribution systems with ...

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13th International Conference on Development in Power System Protection 2016 (DPSP)

作者： Jiang Ni Bin Wang Xinzhou Dong State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100084 China

High impedance faults (HIFs) are easy to occur in collective feeders in wind farms and may cause the cascading of wind generators tripping. This kind of faults is difficult to be detected by traditional relay or fuse due to the limited fault current values and the situation is worse in wind farms. The mostly adopted HIF detection algorithms are based on the 3rd harmonic characteristic of the fault zero-sequence currents, whereas these 3rd harmonics are very easy to be polluted by wind power back-to-back converters. To solve this problem, the typical HIF arc flash based on Mayr's arc model is first built, and the typical fault waveforms of HIF in wind farm are presented. Then the characteristics of high impedance faults are analysed to distinguish the occurrence of HIF from other harmonic interference. After that, the performance of the traditional harmonic based HIF detection algorithm is discussed, and a novel detection algorithm is presented to prevent harmonic interference influence in wind farms.

关键词： distribution system Wind farm high impedance faults harmonic algorithm

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Electrical tree initiation and propagation in silicone rubber under long-term AC aging

Electrical tree initiation and propagation in silicone rubbe...

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Conference on Electrical Insulation and Dielectric Phenomena, (CEIDP)

作者： Yunxiao Zhang Yuanxiang Zhou Ling Zhang Ming Chen Xu Zhang Yanchao Sha State Key Lab of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing Beijing CN State Key Lab of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing China North China Electric Power Research Institute Co Ltd Beijing Beijing CN North China Electric Power Research Institute Co Ltd. Beijing China

关键词： Electrodes Aging Power cables Electric fields Needles Power cable insulation

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