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2015 3rd International Conference on Mechanical engineering and Intelligent Systems(ICMEIS 2015)

作者： Haitao Liu Jian Su Pipei Zhang Hao Bai Shihong Miao China Electric Power Research Institute State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology

The majority of the distribution network is supplied by unilateral power and has a radial distribution, wind farms connected into grid will inevitably bring a certain extent on static voltage of the distributed grid. Furthermore, the randomness of wind farm output will cause the node voltage fluctuations. This paper firstly studies the random flow calculation method including wind power, and analyzes the probability distribution of the grid voltage when wind farms with different capacity accessing by combining the Newton-Raphson method with probability theory. Then establishes a computing model of penetration capacity of wind farms with the constrain of the static voltage stability range. For different values of confidence level α, the results of penetration capacity are different, then we can choose the value α flexibility according to the distribution network security requirements.

关键词： wind farm random output probabilistic load flow penetration capacity

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Two-Stage Optimization Method for Network Reconfiguration and Load Recovery During Power System Restoration

Two-Stage Optimization Method for Network Reconfiguration an...

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IEEE Power and Energy Society General Meeting

作者： Shiwu Liao Wei Yao Xingning Han Jinyu Wen Yunhe Hou State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Department of Electrical and Electronic Engineering The University of Hong Kong

ISBN: (纸本)9781467380416

Network reconfiguration and load recovery (NRLR) during power system restoration is a complex mixed-integer nonlinear programming (MINP) problem, which is difficult to be solved efficiently. To address this problem, this paper proposes a two-stage optimization method for NRLR. The first stage, based on the DC power flow considering frequency characteristics, focuses on the integer variables and provides the optimal plan for transmission line charging and load pick-ups. Then in the second stage, an expanded AC optimal power flow with frequency constraints and load ZIP model is established to minimize the restoration duration of the plan generated by the first stage. The comprehensive restoration plan can be obtained through the iterative optimization process. Case study is undertaken on a 10-machine 39-bus system. Simulation results reveal that the restoration plans obtained from the proposed method are highly efficient, while the computation time satisfies the requirement of online application.

关键词： Load recovery Network reconfiguration Two-stage optimization Power system restoration Power system restoration Network reconfiguration load restoration DC load flow computational time optimization method

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An inrush current mitigation approach of The output transformer for inverter

An inrush current mitigation approach of The output transfor...

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Annual IEEE Conference on Applied Power Electronics Conference and Exposition (APEC)

作者： Zhi Chen Xuejun Pei Li Peng Shunchao Wang State Key Laboratory of Advanced Electromagnetic Engineering and Technology (AEET) Huazhong University of Science and Technology (HUST) Wuhan Hubei China

ISBN: (纸本)9781479967360

When a short circuit fault occurs on the load side of inverter, the control system based on hardware and software current limiting strategy can confine output currents to a certain value. In order to shorten outage time, output voltages should be restored to rated value as soon as possible after the fault is cleared by the circuit breaker of the faulty branch. However, the voltage recovery may cause significant inrush current phenomenon because of magnetic saturation of the output transformer. The high inrush current could lead to voltage distortion and even trigger the protection mechanism. To effectively eliminate the inrush current, this paper proposes an inrush current mitigation approach for three-phase inverter. The phase angle of recovery voltage is controlled so that it is equal to that of fault occurring, which is detected and saved utilizing the double synchronous rotating d-q transformation algorithm. Both simulation and experimental results are provided to demonstrate the feasibility of this method.

关键词： Circuit faults Surges Surge protection Inverters Voltage measurement Control systems Voltage control

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Transformation of Dipeptide‐Based Organogels into Chiral Crystals by Cryogenic Treatment

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Angewandte Chemie 2017年第10期129卷

作者： Xingcen Liu Jinbo Fei Anhe Wang Wei Cui Pengli Zhu Junbai Li Beijing National Laboratory for Molecular Sciences (BNLMS) CAS Key Lab of Colloid Interface and Chemical Thermodynamics Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China State Key Laboratory of Biochemical Engineering Institute of Process Engineering Chinese Academy of Sciences Beijing 100190 China Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen 518055 China

Controlled molecular assembly is an important approach for the synthesis of single‐component materials with diverse functions. Unlike traditional heat treatment or solvent modulation, cryogenic treatment at 77 K enabled the tunable transition of a self‐assembled diphenylalanine organogel into a hexagonal crystal. Under these conditions, the assembled molecules undergo an internal rearrangement in the solid state to form a well‐defined chiral crystal structure. Moreover, these assemblies exhibit enhanced emission. This strategy for the synthesis of single‐component supramolecular assemblies can create new functions by manipulating phase transitions.

关键词： Dipeptide Kristalline Verbindungen Organogele Selbstorganisation Tieftemperaturbehandlung

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Correction: Synthesis of midblock-quaternized triblock copolystyrenes as highly conductive and alkaline-stable anion-exchange membranes

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Polymer Chemistry 2017年第14期8卷 2276-2276页

作者： Meng Zhu Min Zhang Quan Chen Yanxia Su Zhijie Zhang Lei Liu Yiguang Wang Linan An Nanwen Li Science and Technology on Thermostructural Composite Materials Laboratory Northwestern Polytechnical University Xi'an China College of Materials Science and Engineering Beijing Institute of Petrochemical Technology Beijing China Beijing Key Lab of Special Elastomeric Composite Materials Beijing China State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun China State Key Laboratory of Coal Conversion Institute of Coal Chemistry Chinese Academy of Sciences Taiyuan China Department of Materials Science and Engineering Advanced Materials Processing and Analysis Center University of Central Florida Orlando FL 32816 USA

Correction for ‘Synthesis of midblock-quaternized triblock copolystyrenes as highly conductive and alkaline-stable anion-exchange membranes’ by Meng Zhu et al., Polym. Chem., 2017, DOI: 10.1039/c6py02213h.

Correction for ‘Synthesis of midblock-quaternized triblock copolystyrenes as highly conductive and alkaline-stable anion-exchange membranes’ by Meng Zhu et al., Polym. Chem., 2017, DOI: 10.1039/c6py02213h.

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Innenrücktitelbild: Isolated Single Iron Atoms Anchored on N‐Doped Porous Carbon as an Efficient Electrocatalyst for the Oxygen Reduction Reaction (Angew. Chem. 24/2017)

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Angewandte Chemie 2017年第24期129卷

作者： Yuanjun Chen Shufang Ji Yanggang Wang Juncai Dong Wenxing Chen Zhi Li Rongan Shen Lirong Zheng Zhongbin Zhuang Dingsheng Wang Yadong Li Department of Chemistry Tsinghua University Beijing 100084 China Beijing Synchrotron Radiation Facility Institute of High Energy Physics Chinese Academy of Sciences Beijing China State Key Lab of Organic-Inorganic Composites and Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical Technology Beijing 100029 China

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Isolated Single Iron Atoms Anchored on N‐Doped Porous Carbon as an Efficient Electrocatalyst for the Oxygen Reduction Reaction

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Angewandte Chemie 2017年第24期129卷

The development of low‐cost, efficient, and stable electrocatalysts for the oxygen reduction reaction (ORR) is desirable but remains a great challenge. Herein, we made a highly reactive and stable isolated single‐atom Fe/N‐doped porous carbon (ISA Fe/CN) catalyst with Fe loading up to 2.16 wt %. The catalyst showed excellent ORR performance with a half‐wave potential ( E 1/2 ) of 0.900 V, which outperformed commercial Pt/C and most non‐precious‐metal catalysts reported to date. Besides exceptionally high kinetic current density ( J k ) of 37.83 mV cm −2 at 0.85 V, it also had a good methanol tolerance and outstanding stability. Experiments demonstrated that maintaining the Fe as isolated atoms and incorporating nitrogen was essential to deliver the high performance. First principle calculations further attributed the high reactivity to the high efficiency of the single Fe atoms in transporting electrons to the adsorbed OH species.

关键词： Einzelatomkatalysatoren Eisen Elektrokatalysatoren Poröse Kohlenstoffe Sauerstoffreduktion

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Inside Back Cover: Isolated Single Iron Atoms Anchored on N-Doped Porous Carbon as an Efficient Electrocatalyst for the Oxygen Reduction Reaction (Angew. Chem. Int. Ed. 24/2017)

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Angewandte Chemie International Edition 2017年第24期56卷

作者： Yuanjun Chen Shufang Ji Dr. Yanggang Wang Dr. Juncai Dong Dr. Wenxing Chen Zhi Li Rongan Shen Dr. Lirong Zheng Prof. Zhongbin Zhuang Prof. Dr. Dingsheng Wang Prof. Dr. Yadong Li Department of Chemistry Tsinghua University Beijing 100084 China Beijing Synchrotron Radiation Facility Institute of High Energy Physics Chinese Academy of Sciences Beijing China State Key Lab of Organic-Inorganic Composites and Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical Technology Beijing 100029 China

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Research of HTS Application on Tokamak Magnets

Research of HTS Application on Tokamak Magnets

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2015 International Conference on Power Electronics and Energy engineering（PEEE 2015）

作者： L.Ren X.Z.Deng Y.Xu H.Liu J.D.Li J.Shi Y.J.Tang State Key Laboratory of Advanced Electromagnetic Engineering and Technology R&D Center of Applied Superconductivity Huazhong University of Science and Technology

ISBN: (纸本)9781510807648

in this paper,the application feasibility of HTS tapes on tokamak magnets is discussed and the existing four kinds of HTS high current conductors are ***,an YBCO conductor structure suitable for a 10 GJ tokamak TF magnet is designed and the current carrying capacity is *** simulation result shows that the critical current of the YBCO conductor is about 75 kA@10 T,30 K.

关键词： HTS Application Tokamak Magnets YBCO conductor

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A Novel Modulation Method Applied in Quasi-Z-Source Based Cascaded PV System Suffering Module Mismatch

A Novel Modulation Method Applied in Quasi-Z-Source Based Ca...

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Annual Conference of the IEEE Industrial Electronics Society

作者： Cheng Wang Kai Zhang Liming Liu Wenxin Liu State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology ABB Inc. Electrical and Computer Engineering Lehigh University

ISBN: (纸本)9781479917631

Quasi-Z-source based modular cascaded multilevel converter featuring both the advantages of multilevel converter like modularity, scalability, distributed maximum power point tracking (MPPT) capability and the advantages of quasi-Z-source network (qZSN) like high efficiency, no consideration for annoying switching dead-zone, wide dc voltage boosting range etc. is a promising option for high power solar photovoltaic (PV) system. Nevertheless, inherent mismatch and varied operating conditions (both called module-mismatch) are still the issues to be disclosed. Asymmetrical active power harvesting among individual PV converter modules resulting from module-mismatch will fluctuate dc voltages and polarize the distribution of the alternating terminal voltage and may derivatively destroy the coordination between the QZS and the H-bridges (HB). In this paper, a novel modulation method for qZSN based cascaded modular multilevel converter with two modes which are low-loss mode for normal operation and extended mode for module-mismatch operation is proposed. With the former mode, the switching times are reduced greatly and then low the switching loss. When encountered by module-mismatch, extended mode is able to re-distribute power and then to balance dc-link voltages. Based on the modulation method, a reactive power compensation algorithm (RPCA) with larger operating range is applied in order to mitigate the polarization of ac voltage. Finally, a 3MW/12kV system with the proposed modulation and control strategy is developed in Matlab/Simulink platform. Simulation results are presented to demonstrate the effectiveness of the proposed technology.

关键词： Quasi-Z-source Cascaded PV Module-mismatch Modulation Reactive power compensation modulation mode reactive compensation multistage converter VOLTS DIRECT CURRENT cascades maximum power point trackers Polydnaviridae VOLTS ALTERNATING CURRENT Modularity

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