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A massive grid-connected power accumulator battery testing system using hybrid AC-DC microgrid

Diangong Jishu Xuebao/Transactions of China Electrotechnical Society 2014年 29卷 449-453页

作者： Long, Bo Sun, Hongbin Wang, Bin Yao, Shuqing Fang, Xu Yao, Gaoxiang University of Electronic Science and Technology Chengdu610054 China State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University Beijing100084 China Bohai New Century Machinery Manufacturing Co. Ltd. TianJin300280 China

Nowadays, the network mode of the most energy recovery power battery testing instruments adopts AC-microgrid, which has the drawbacks of low energy recovery efficiency, complicated power circuit topology, cumbersome of the control algorithms. Aiming at these issues, a hybrid AC-DC microgrid system which is based on the power battery testing system has been put forward in this paper. The proposed scheme is composed by an energy storing system, a bidirectional DC-DC converter for test experiment, the grid-side loads, compared with conventional scheme, the proposed scheme has the merits of higher energy recovery efficiency, simplified power circuit for testing instruments. ©, 2014, Diangong Jishu Xuebao/Transactions of China Electrotechnical Society. All right reserved.

关键词： DC-DC converters

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Improve the Conversion Rate and Selectivity of Aromatic Monomers in Lignin Photocatalytic Conversion Reaction Via Phase Junction Cadmium Sulphide Nanoparticles and External Hydrogen Supplier

SSRN

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SSRN 2023年

作者： Yue, Zongyang Shao, Shibo Yu, Jialin Lu, Guanchu Wei, Wenjing Huang, Yi Zhang, Kai Wang, Ke Fan, Xianfeng Institute for Materials and Processes School of Engineering The University of Edinburgh EdinburghEH9 3BF United Kingdom Petrochemical Research Institute PetroChina Company Limited Beijing102206 China Beijing Key Laboratory of Ionic Liquids Clean Process CAS Key Laboratory of Green Process and Engineering State Key Laboratory of Multiphase Complex Systems Innovation Academy for Green Manufacture Institute of Process Engineering Chinese Academy of Sciences Beijing100190 China Longzihu New Energy Laboratory Zhengzhou Institute of Emerging Industrial Technology Henan University Zhengzhou450000 China Beijing Key Laboratory of Emission Surveillance and Control for Thermal Power Generation North China Electric Power University Beijing102206 China

Photocatalysis has the potential for lignin valorisation to generate functionalised aromatic monomers, but its large-scale application has been limited by the slow conversion rate and the low selectivity to desirable products. In this work, record-high lignin model compound Cβ-O bonds cleavage rate and excellent selectivity to aromatic monomers has been achieved over the development of new hexagonal-cubic phase junction CdS nanoparticles, enhanced external hydrogen donor supply and hydrogen transfer, and improved separation efficiency of photo-excited electron-hole pairs. Water is employed as external hydrogen supplier, resulting in significant increase in the conversion rate of 2-Phenoxy-1-phenylethanol (PP-ol) as lignin model from 21.8% to 100% and the selectivity of aromatic monomers from ~45% to ~94% under 1h of visible light irradiation. 2-phenoxyacetophenone (PP-one) as by-product from PP-ol conversion can be further completely cleaved to aromatic monomers with assistance of TEA and reaction time is reduced from 2-12 hrs to10 min under visible-light irradiation. © 2023, The Authors. All rights reserved.

关键词： Lignin

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Effect of surface topography and morphology on space charge packets in polyethylene

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Journal of Physics: Conference Series 2009年第1期183卷

作者： Zhou Yuanxiang Wang Yunshan Wang Ninghua Sun Qinghua State Key Lab of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China China Electric Power Research Institute Haidian District Beijing 100085 China

Polyethylene (PE) is a major kind of internal insulating material. With great progresses of space charge measurement technologies in the last three decades, lots of researches are focused on space charge in PE. The heat pressing and annealing condition of polyethylene affect its morphology obviously. During the heat pressing, the surface of PE forms different surface topographies because of different substrate materials. Surface topography has great relation to the epitaxial crystallization layer and influences the space charge characteristic of PE dramatically. This paper studied the formation process of different surface topographies and their micrographic characters in low density polyethylene (LDPE). pulsed electro-acoustic (PEA) method was used to measure the space charge distribution of samples with different surface topographies and morphologies in LDPE. The effect of surface topography and morphology to space charge packet were studied. The surface topography has great influence on space charge packet polarity and morphology has influence on both movement speed rate and polarity of space charge packet.

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Analysis of electrical tree ageing in silicone rubber by physicochemical approach

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Journal of Physics: Conference Series 2009年第1期183卷

作者： Y X Zhou Q Nie Z Z Chen R Liu State Key Lab of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China Department of Electrical Engineering Zhengzhou University Zhengzhou 450001 China

In this paper, the characteristics of electrical tree ageing in silicone rubber (SIR) under AC voltage were studied. The electrical tree initiation rate is 20% after the application of 6 kV AC voltage for 1000 hours. Samples are separated into three kinds according to processes of electrical tree formation: virgin samples without voltage application, non-treed samples without electrical tree formation after 1000 hours and treed samples with electrical tree formation after 1000 hours. Certain physicochemical diagnostic tests were carried out to understand the degradation of material, ascribed to long-time voltage application, using differential scanning calorimetry (DSC) and thermogravimetric-differential thermal analysis (TG-DTA). Physicochemical analyses, especially the DSC results, show that no additional phases are formed in the processes of electrical tree ageing in SIR. Reduction of the melting point and crystallinity of SIR is observed in the sequence of virgin samples, non-treed samples and treed samples. The activation energy values were calculated from the TG-DTA data. Compared to virgin samples, obvious reduction of activation energy value is observed in non-treed samples. Degradation in SIR has already occurred before electrical tree formation and charge injection and extraction by high field electrode under AC voltage is regarded as the reason.

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Polymeric insulating materials characteristics for high-voltage applications

Nature Reviews Electrical Engineering

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Nature Reviews Electrical Engineering 2024年 516-528页

作者： Tian-Yu Wang Gui-Xin Zhang Zhi-Min Dang Jie Mao Boya Zhang State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China Department of Chemical and Biomolecular Engineering University of California Los Angeles CA USA School of Chemistry and Chemical Engineering State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering Ningxia University Yinchuan China State Key Laboratory of Electrical Insulation and Power Equipment Xi’an Jiaotong University Xi’an China

Large-scale power system transmission and transformation equipment operates in high-voltage environments, placing notable requirements on the insulation strength of polymers used in core insulation frameworks. Increasing the polymer insulation performance in high-voltage environments is crucial for protecting large-capacity and integrated power equipment and ensuring the safe and stable operation of electrical devices. Here, we discuss the phenomena and the underlying mechanisms of bulk breakdown and surface flashover that lead to insulation failure in polymers and present relative strategies to increasing the performance of the insulating materials. We analyse the challenges faced by polymeric insulating materials in various extreme environments and the strategies to address them. Finally, we identify key challenges and highlight future directions and opportunities for the development of reliable polymeric insulating materials.

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Performance analysis of a photovoltaics aided coal-fired power plant

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Energy Procedia 2019年 158卷 1348-1353页

作者： Mingkun Jiang Yuexia Lv Tiankun Wang Zunqiang Sun Jianmin Liu Xinhai Yu Jinyue Yan Key Laboratory of Pressure Systems and Safety (MOE) School of Mechanical Engineering East China University of Science and Technology Shanghai 200237 China State Key Laboratory of Clean and Efficient Coal-fired Power Generation and Pollution Control Guodian Science and Technology Research Institute Nanjing 210023 China Applied Energy Innovation Institute Ningbo 315201 China School of Mechanical & Automotive Engineering Qilu University of Technology (Shandong Academy of Sciences) Jinan China China Energy Group Beijing 100011 China School of Business Society and Technology Mälardalen University Västerås Sweden School of Chemical Science and Engineering Royal Institute of Technology Stockholm Sweden

In this article, integration of photovoltaics (PV) into a coal-fired power plant was proposed. The performance including economic analysis and environmental impact was conducted by a case study in the northwest area of China. The results show that the PV system can replace part of auxiliary power consumption using renewable electricity to reduce internal power consumption and the emissions. Due to the feature of the integration into a power plant, the curtailment of solar PV electricity does not occur compared to stand-alone PV system. The investment cost, operation and maintenance (O&M) expenditure were feasible compared with other PV power generation plants.

关键词： photovoltaics coal-fired power plants auxiliary power consumption

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Effects of nonlinear gradient index on radiative heat transfer in a one-dimensional medium by the DRESOR method

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Journal of Physics: Conference Series 2012年第1期369卷

作者： Z C Wang Q Cheng G H Wang Z F Huang H C Zhou State Key Laboratory of Coal Combustion Huazhong University of Science and Technology Wuhan 430074 Hubei People's Republic of China State Key Laboratory of Control & Simulation of Power System & Generation Equipment Department of Thermal Engineering Tsinghua University Beijing 10084 P. R. China To whom any correspondence should be addressed

The DRESOR (Distribution of Ratios of Energy Scattered by the medium Or Reflected by the boundary surface) method is applied for radiative heat transfer in a one-dimensional medium with a nonlinear gradient index and gray boundary surfaces. In this proposed method, the DRESOR values calculated by the Monte Carlo method express quantitatively the impact of scattering on radiative transfer and the radiative intensity with high directional resolution of high precision can be easily obtained. With given media characteristics and boundary conditions, the temperature and radiative flux distributions inside the medium are calculated under the condition of radiative equilibrium. It is shown, in the cases studied, that the DRESOR method has a good accuracy. The temperature distributions have a node with different kinds of sine changed gradient index distributions under the same boundary emissivity. The impact of the gradient index on the radiative heat transfer is considerable, and the same as that of the ratios of its amplitude and average index. Besides, the effects of optical thickness, boundary emissivity and scattering phase function on radiative transfer also should be paid adequate attention.

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Cufe2o4@Ncnts-Functionalized Ceramic Microfiltration Membrane for Antibiotic Oxidation and Fouling control Via Heterogeneous Electro-Fenton Reaction

SSRN

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SSRN 2024年

作者： Zhang, Zixin Huang, Guohe Li, Yongping Yao, Yao Zhang, Peng Chen, Xiujuan Ren, Shaojie Luo, Yifei Zhang, Yuanzheng State Key Joint Laboratory of Environmental Simulation and Pollution Control School of Environment Beijing Normal University Beijing100875 China State Key Joint Laboratory of Environmental Simulation and Pollution Control China-Canada Center for Energy Environment and Ecology Research UR-BNU School of Environment Beijing Normal University Beijing100875 China Environmental Systems Engineering Program University of Regina ReginaSKS4S 0A2 Canada Institute for Energy Environment and Sustainable Communities University of Regina ReginaS4S 0A2 Canada Department of Civil Engineering The University of Texas at Arlington ArlingtonTX United States Shandong Key Laboratory of Water Pollution Control and Resource Reuse School of Environmental Science and Engineering Shandong University Qingdao266237 China College of Environmental Science and Engineering North China Electric Power University Beijing102206 China

Herein, we reported an electrocatalytic ceramic microfiltration membrane functionalized with CuFe2O4 nanoparticles supported by nitrogen-doped carbon nanotubes (NCNTs). The synergistic catalysis between Fe and Cu induced a continuous ·OH generation. The active Fe(II) and Cu(I) sites decomposed the in-situ generated H2O2 into ·OH. The electron transfer from the external circuit and Cu(I) to Fe(III) drove the regeneration of Fe(II). The interfacial electron transfer from CuFe2O4 to NCNTs decreased the electron density of Fe and Cu, thus facilitating the redox cycles of Fe(III)/Fe(II) and Cu(II)/Cu(I). Furthermore, the Fe and Cu sites at the interface of CuFe2O4 and NCNTs displayed a superior ability to non-interface sites in producing ·OH. At near-neutral pH, the electrocatalytic membrane delivered excellent tetracycline removal kinetics (0.0134 min-1) and significantly alleviated the organic fouling occurring on the membrane. These findings shed new light on the development of new-generation membranes with catalytic oxidation capabilities for water treatment. © 2024, The Authors. All rights reserved.

关键词： Antibiotics

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Optimal power and energy sizing of compressed air energy storage in distribution network using multiparametric programming

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IOP Conference Series: Earth and Environmental Science 2021年第1期675卷

作者： Fan Chen Zhongjie Guo Qiyou Lin Xiaodai Xue Yuguang Xie Shengwei Mei State Grid Anhui Electric Power Research Institute Hefei 230601 China State Key Lab of Control and Simulation of Power Systems and Generation Equipments (Dept. of Electrical Engineering Tsinghua University) Haidian District Beijing 100084 China State Grid Wuhu Electric Power Supply Company Wuhu 241027 China

As a new type of mechanical energy storage, compressed air energy storage (CAES) has attracted wide attention in recent years. This paper studies the optimal sizing problem of CAES in power distribution network (PDN). CAES plays a role in shaving the peak and filling the valley at demand side and thus reduces the operation cost of PDN to purchase electricity from the main grid. A multi-parametric linear programming (MP-LP) model is formulated where the power and energy capacities of CAES are regarded as parameters; the parameterized optimal value function (OVF) provides a graphical tool to describe the impact on operation cost of CAES configuration, which helps determine the planning strategy in a visual manner. The visualized results reveal not only the optimal solution, but also some useful information, like the sensitivity of operation cost to parameters. Case studies conducted on the IEEE 33-bus distribution system verifies the effectiveness of the proposed method.

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印度大停电与继电保护的三大功能

印度大停电与继电保护的三大功能

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2012年中国智能电网学术研讨会

作者： DONG Xin-zhou 董新洲 CAO Run-bin 曹润彬 WANG Bin 王宾 SHI Shen-xing 施慎行 Dominik Bak State Key Lab of Control and Simulation of Power Systems and Generation Equipments Tsinghua Universi 清华大学电力系统及发电设备安全控制和仿真国家重点实验室北京 100084

简介了印度电网在2012年7月30日和7月31日发生的两起大停电事故。两起事故均起源于同一回输电线路距离保护Ⅲ段因过负荷保护动作跳闸，并导致其他设备继电保护的不合理动作而引发连锁跳闸，造成大面积停电。印度大停电事故暴露了现有电... 详细信息

简介了印度电网在2012年7月30日和7月31日发生的两起大停电事故。两起事故均起源于同一回输电线路距离保护Ⅲ段因过负荷保护动作跳闸，并导致其他设备继电保护的不合理动作而引发连锁跳闸，造成大面积停电。印度大停电事故暴露了现有电力系统的脆弱性，尤其是继电保护在过负荷和系统振荡情况下的动作缺陷。基于对停电事故中继电保护行为的分析，提出了满足现代电网需求的继电保护三大功能：面向系统安全的系统保护功能、预防性保护功能和快速切除故障设备功能。

关键词：停电事故继电保护过负荷故障处理

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