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8th Renewable power generation Conference, RPG 2019

作者： Shilong, Qiu Hui, Li Lijiao, Gong Bin, Wang Zhaoseng, Chai You, Wu Department of Mechanical and Electrical Engineering Shihezi University Shihezi China State Key Laboratory of Power Drivetrain Equipment and System Security Chongqing University Chongqing China State Key Lab of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Haidian District Beijing China

ISBN: (纸本)9781839531255

The shafting drivetrain of the doubly fed wind turbine is the part with the highest failure rate. The electromagnetic torque fluctuation caused by the grid fault easily results in the torsional vibration fatigue loss of the shaft. Accordingly, the influences of drivetrain fatigue life loss under different grid faults require investigation. Firstly, the four-mass model of the drivetrain is constructed on the basis of MATLAB/Simuhnk. Secondly, the electromagnetic torque response under short-circuit fault of the grid is obtained via model simulation. Finally, the effects of different types of grid faults on the fatigue life of the drivetrain are analysed through Mlife. Results show that the electromagnetic torque fluctuation load generated by grid fault has no apparent influence on the fatigue life of the drivetrain in the short term. but the cumulative effect of short-term damage will aggravate the fatigue life loss of the drivetrain and increase the failure risk of the component. The electromagnetic torque generated by the three-phase symmetrical short-circuit is the most violent and has the maximum effect on the fatigue life of the drivetrain. © 2019 Institution of Engineering and Technology. All rights reserved.

关键词： Timing circuits

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First stirling-type cryocooler reaching lambda point of ~4He(2.17K) and its prospect in Chinese HUBS satellite project

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Science Bulletin 2019年第4期64卷 219-221页

作者： Jue Wang Changzhao Pan Tong Zhang Kaiqi Luo Xiaotong Xi Xianlin Wu Jianpeng Zheng Liubiao Chen Junjie Wang Yuan Zhou Hai Jin Wei Cui University of Chinese Academy of Sciences CAS Key Laboratory of Cryogenics Technical Institute of Physics and Chemistry Chinese Academy of Sciences Laboratoire National de Métrologie Et d'essais-Conservatoire National des Arts et Métiers (LNE-Cnam) State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Department of Physics and Center for Astrophysics Tsinghua University

The issue of "missing baryons” is always an unsolved mystery in galaxy cosmology, and an important reason for the great uncertainty of the galaxies' formation and evolution. To find the "missing" baryons, extra high-resolution spectral observation and imaging of the soft X-ray band (<1 kev) is required. However, the existing observation methods cannot meet this requirement. Therefore, Tsinghua University leads and proposes the Chinese "Hot Universe Baryon Surveyor (HUBS)" satellite program.

关键词： missing baryons HUBS missing

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Fault diagnosis for PV arrays considering dust impact based on transformed graphical features of characteristic curves and convolutional neural network with CBAM modules

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Applied Energy 2024年 355卷

作者： Jiaqi Qu Qiang Sun Zheng Qian Lu Wei Hamidreza Zareipour School of Instrumentation and Optoelectronic Engineering Beihang University Beijing China State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing China School of Electronics and Information Engineering Beihang University Beijing China The Department of Electrical and Computer Engineering University of Calgary Calgary Canada

Various faults can occur during the operation of photovoltaic (PV) arrays, and both dust-affected operating conditions and various diode configurations complicate the faults. However, current methods for fault diagnosis based on I-V characteristic curves usually do not effectively use all the distinguishable information contained in the I-V curves or often rely on calibrating the field characteristic curves to standard test conditions (STC). It is difficult to apply these methods in practice and accurately identify multiple complex faults with similarities in different blocking diode configurations of PV arrays under the influence of dust. Therefore, a novel fault-diagnosis method for PV arrays that considers the impact of dust is proposed. In the pre-processing stage, the Isc-Voc normalized Gramian angular difference field (GADF) method is presented, which normalizes and transforms the resampled PV array characteristic curves from the field, including I-V and P-V, to obtain transformed graphical feature matrices. Subsequently, in the fault diagnosis stage, the convolutional neural network (CNN) model with convolutional block attention modules (CBAM) is designed to classify faults, which identifies complex fault types from the transformed graphical matrices containing complete discriminative fault information. In addition, the performances of different graphical feature transformation and CNN-based classification methods are compared using case studies. The results indicate that the developed method for PV arrays with different blocking diode configurations under various operating conditions has high fault diagnosis accuracy and reliability.

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Investigation on Insulating Properties of Epoxy Resin Impregnated Paper Affected by Curing Agents and Accelerator Contents

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IEEE Transactions on Dielectrics and Electrical Insulation 2025年

作者： Teng, Chenyuan Ding, Yichao Zhou, Yuanxiang Zhao, Lei Zhang, Yunxiao Chen, Haoran Zhang, Youbing Zhejiang University of Technology College of Information Engineering Hangzhou310023 China Nankai University China and College of Electronic Information and Optical Engineering Tianjin300350 China Zhejiang Testing & Inspection Institute for Mechanical and Electrical Products Quality Co. Ltd Hangzhou310051 China Tsinghua University State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Beijing100084 China State Grid Xinxiang Electric Power Supply Company Xinxiang453002 China

The curing formula is vital to the performance of epoxy resin impregnated paper (RIP) material. This work explored the effect of curing agents and accelerator contents on the thermal and electrical properties of RIP material. It was found that the RIP material cured with 1phr accelerator has the optimal glass transition temperature, electrical conductivity, dielectric loss and DC breakdown strength compared with RIP material cured by 0.5phr, 2phr, and 3phr accelerator. The RIP material cured with MEHHPA has better thermal and insulating properties compared with the RIP material cured with METHPA. The existence of the crepe paper amplifies the influence of accelerator and curing agent for the hydroxyl groups affect the curing process as well as the chain segment arrangement. This study provides the research support for the design of the curing formula for RIP insulation used in DC bushing. © 1994-2012 IEEE.

关键词： Dielectric losses

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Contaction of Atoms for Outstanding Dielectric Characteristics in Kx-Passivated Polymer Dielectrics

SSRN

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SSRN 2022年

作者： Li, Xiao-Fen Wang, Tian-Yu Liu, Bai-Xin Liu, Jian-Bo Zhang, Gui-Xin Wang, Zhong Lin School of Materials Science and Engineering Tsinghua University Beijing100084 China State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100084 China CAS Center for Excellence in Nanoscience Beijing Institute of Nanoenergy and Nanosystems Chinese Academy of Sciences Beijing100083 China School of Nanoscience and Technology University of Chinese Academy of Sciences Beijing100049 China School of Material Science and Engineering Georgia Institute of Technology AtlantaGA30332 United States

High dielectric characteristics polymer dielectrics are crucial for high-power, high-integration, and high-energy storage density electrical devices and film capacitors. However, polymer dielectrics accumulate much charge during operation, causing local electric field distortion and flashover or breakdown. The deep-level defect state (electron/hole accumulation center) is a fundamental factor affecting dielectric strength. Unfortunately, related research, especially on passivating deep-level defects in polymer dielectrics, is minimal. In this paper, based on experiments and first-principles calculations, it is found that KX (X=F, Cl, Br, I) effectively passivates deep-level defect states in polymer dielectrics. Further analysis of the physical passivation mechanism reveals that the deep-level defect cation passivation principle is the cation dipole effect on polymers. The principle of anion passivation of deep-level defects by suspending anions and cations is the key to producing more stable C covalent bonds. This stable covalent bond transfers the local charge from the C with the lone electron pair that originally contains the hanging bond. Therefore, some transfer occurs and the anion implements effective passivation. This paper addresses the design of high-performance polymer dielectrics, providing a reference for experimental and theoretical analyses. © 2022, The Authors. All rights reserved.

关键词： Passivation

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Consensus-based Nodal Pricing Mechanism for Automated Demand Response Considering Congestion Management on Distribution Networks

Consensus-based Nodal Pricing Mechanism for Automated Demand...

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IEEE/IAS Industrial and Commercial power System Asia (I&CPS Asia)

作者： Gang Luo Yijing Chen Yue Zhao Yujun He Chao Gong Chen Zhao Power Dispatching and Control Center Guangdong Power Grid Co. Ltd Guangzhou China Electric Power Research Institute China Southern Power Grid Co. Ltd Guangzhou China State Key Lab of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing China

ISBN: (数字)9781728143033

ISBN: (纸本)9781728143040

This paper investigates a consensus-based nodal pricing mechanism for incenting automated demand response in the deregulated market environment. These small-scale customers are autonomously managed by automated demand response (DR) controllers, which are capable of scheduling user's load devices to follow a day-ahead 24h price signal from electricity distribution companies (EDC). First, an alternating current optimal power flow (ACOPF) on the distribution network is formulated considering the participation of automated DR. Then, a consensusbased approach is exploited to adjust the nodal price and DR profile for each customer using primal-dual decomposition. The proposed mechanism is compared with a day-ahead pricing (DAP) program on a test distribution network and numerical results have shown promising performance in supporting the congestion management on the distribution grid.

关键词： Pricing Load management Load modeling power grids Mathematical model Dispatching Companies

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Planning of active power distribution network based on source-network-load collaborative optimization

Planning of active power distribution network based on sourc...

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The 16th IET International Conference on AC and DC power Transmission (ACDC 2020)

作者： Z. Jiang Q. Yu A. Li Y. Xiong G. Long Y. Liu Ministry of Education (Northeast Electric Power University) Key Laboratory of Modern Power System Simulation and Control & Renewable Energy Technology Jilin 132012 China Tsinghua University State Key Laboratory of Power Systems Department of Electrical Engineering Beijing China

With the fast development of renewable energy generation, the randomness and volatility seriously threaten the stability of the power system. In order to improve the consumption rate of renewable energy and the economic benefit, the source-network-load collaborative optimization is put forward and widely used in the power system. And the active power distribution network which consists of the energy storage devices and flexible load is the best carrier to realize it. Based on the active power distribution network planning, this paper firstly designs an economic index covering construction cost and operation cost as the optimization objective. Then with the physical constraints consisting of the physical features of generation units, energy storage devices and flexible load, the source-network-load collaborative optimization model of active power distribution network is established. Finally, a case of city distribution network is presented to verify the effect of source-network-load collaborative optimization and the efficiency of the optimization model.

关键词： power distribution planning power distribution reliability distributed power generation power distribution economics renewable energy sources optimisation energy storage

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Retraction notice to “Multi-objective planning of microgrid based on renewable energy sources and energy storage system” [J. Energy Storage 68 (2023) 107803]

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Journal of Energy Storage 2025年 117卷

作者： Hao Tian Keqing Wang Xiufeng Cui Zexi Chen Ergang Zhao Sara Saeedi School of Automation Wuxi University Wuxi 214105 China State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Haidian District Beijing 100086 China Beijing Sifang Engineering Co. Ltd Beijing 100085 China State Grid Beijing Urban Power Supply Company Beijing 100034 China Electrical Engineering Department Sun-Life Company Baku Azerbaijan

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Research on reliability of Ad hoc network communication in UAVs formations 6

Research on reliability of Ad hoc network communication in U...

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6th IEEE International Symposium on Electromagnetic Compatibility, ISEMC 2019

作者： Li, Yanchu Li, Shufang Ding, Qingqing Wang, Chao School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing China State Key Lab of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Dept. of Electrical Engineering Beijing China

ISBN: (纸本)9781728144160

As an important performance index of the UAV Ad hoc network, network reliability is a great significance for the performance evaluation of the UAV network system, and provides a direction for the selection of the UAVs formations. In this paper, based on the 3D Gauss Markov moving model, we modeled the motion mode of the UAV group. By using the Weibull distribution to sample the failure of the fleet, and through the correlation matrix which characterizes the connectivity state of network nodes in the time domain, we studied and compare the reliability of the self-organizing network of the UAV group with different formations. It provides a basis for selecting the formations of the UAVs for different network requirements. © 2019 IEEE.

关键词： Reliability

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Electron relaxation properties of Ar magnetron plasmas

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Plasma Science and Technology 2018年第3期20卷 87-94页

作者： Xinjing CAI Xinxin WANG Xiaobing ZOU Department of Electrical Engineering Northeast Electric Power UniversityJilin 132012People's Republic of China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Tsinghua UniversityBeijing 100084People's Republic of China

An understanding of electron relaxation properties in plasmas is of importance in the application of *** improved multi-term approximation of the Boltzmann equation is employed to study electron transport and relaxation properties in ***,inelastic and nonconservative collisions between electrons and neutral particles are *** expressions for the transport coefficients are obtained using the expansion coefficients and the collision operator *** solutions of the matrix equations for the expansion coefficients are also *** calculations of the Reid model are presented to demonstrate the accuracy of the improved multi-term *** is shown that the twoterm approximation is generally not accurate enough and the magnetic fields can reduce the anisotropy of the velocity distribution *** electron relaxation properties of Ar plasmas in magnetrons for various magnetic fields are *** is demonstrated that the energy parameters change more slowly than the momentum parameters.

关键词： electron transport electron relaxation Boltzmann equation multi-term approximation

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