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Power Systems and Electrical technology (PSET), IEEE International Conference on

作者： Siyuan Cheng Manling Dong Xi Shi Lei Guo Wei Yao Wei Wang Yunrui Ma State Grid Henan Electric Power Corporation Research Institute Zhengzhou China State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

With the development of ZnO arresters towards high voltage gradient and miniaturization, more stringent requirements are put forward for ZnO varistor ceramics, and higher requirements are also placed on the uniformity of the distribution of added components in ZnO varistor ceramic powders. this paper, ZnO varistor powders were prepared by the chemical precipitation method, and ZnO varistor ceramics were prepared at different sintering The properties of the samples were analyzed by various characterization methods, and their microstructure and electrical properties were studied. The experimental findings indicate that the mean grain size of ZnO varistor ceramics become larger as the sintering temperature increases, and the grain boundary nonlinearity coefficient and potential barrier height first increase and then decrease. When the sintering temperature is 1050°C, the grain size of the ZnO varistor ceramic sample is better, the grain boundary barrier height is the highest, and the comprehensive electrical properties are better. Compared with the common 1100°C$\sim$1200°C in the literature, it not only reduces the energy consumption but also improves the performance of ZnO varistor ceramics. It is speculated that the uniform distribution of doping ions before sintering reduces the sintering temperature. The lower temperature reduces the volatilization of oxide additives such as bismuth oxide and avoids abnormal grain growth.

关键词： Varistors Temperature distribution Precipitation Powders II-VI semiconductor materials Sintering Zinc oxide

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Fine Tune or not? Evaluation of Transfer Methods for Power System Transient Stability Analysis

Fine Tune or not? Evaluation of Transfer Methods for Power S...

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International Conference on Power System technology (POWERCON)

作者： Zhouping Li Wei Yao Yanhao Huang Zhongtuo Shi Yong Tang Jinyu Wen State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

ISBN: (纸本)9781665407380

Many methods based on deep learning (DL) have been developed to handle the power system stability analysis problem with satisfactory results. A well-trained DL model on the source domain may encounter the performance reduction problem when applied to a target domain of different distributions. Thus, transfer learning is needed to transfer knowledge learned from the source domain to the target domain which can reduce the cost of collecting more data and labels. As a commonly used scheme, fine-tuning is thought to be able to share the ability to extract high-level features to the target model by reusing the parameters of the pretrained model. Several fine-tune schemes are compared to evaluate the benefits brought by fine-tuning. The results show that freezing the layers of the DL model may restrict the tuning process in terms of convergence speed and test accuracy. A simple but effective mixed dataset training scheme is demonstrated to work better than fine-tune schemes.

关键词： Training Deep learning Analytical models Simulation Transfer learning Power system stability Feature extraction

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Research on the Influence of Terrain Curved-Surface on Lightning Parameters 4

Research on the Influence of Terrain Curved-Surface on Light...

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4th IEEE China International Electrical and Energy Conference, CIEEC 2021

作者： Zhao, Hailong Zhang, Dandan Pang, Songling Pan, Wenwu Yang, Liguo Wei, Shixun Electric Power Science Research Institute of Hainan Power Grid Co. Ltd. Hainan Power Grid Tropical Smart Grid Laboratory Haikou China Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan China

ISBN: (纸本)9781728171494

Lightning parameters are indispensable key parameters in lightning protection design. Based on the ground lightning data from the Hainan lightning location system in 2009, the relationships between lightning parameters (the average lightning current amplitude of total ground flashover, the proportion of positive and the negative flashover, and total ground flashover density) and terrain curved-surface parameters (slope, slope aspect, and slope position) are studied by means of GIS spatial analysis and mathematical statistics. Firstly, it is concluded that there is a cubic function relationship between the average lightning current amplitude of total ground flashover and slope. The proportion of positive flashover decreases with the increase of slope, and the distribution of total ground flashover density features U-shape with the increase of slope. The lightning protection should be strengthened for the transmission lines built on the mountain with the slope below 10° or above 48°. In addition, when the slope aspect is in the southwest direction, the average lightning current amplitude of total ground flashover and total ground flashover density are the lowest, while the proportion of positive flashover is the largest among all slope aspects. So some anti-backflashover measures should be taken for transmission lines built in the southwest slope aspect. Besides, the average lightning current amplitudes of total ground flashover are the largest and the total ground flashover densities are the highest in ridge and valley among all slope position. Some special lightning protection measures should be considered to be taken in ridge and valley. © 2021 IEEE.

关键词： Flashover

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Assessment of Cao-Based Sorbent/Spinel Catalyst Composites for the Oxidative Dehydrogenation of Ethane in Isothermal In-Situ Co2 Capture and Utilization

SSRN

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SSRN 2023年

作者： Zhang, Xiaoyu Wei, Wei Ma, Jingran Zhang, Tiangang Wang, Yuan Sun, Haohan Wang, Feng Liu, Wenqiang State Key Laboratory of Coal Combustion School of Energy and Power Engineering Huazhong University of Science and Technology Wuhan430074 China China Energy Group Coal Coking Co. Ltd Wuhai016000 China State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan430074 China Huazhong University of Science and Technology China

In this study, a comparative analysis of the isothermal in-situ CO2 capture and utilization (ICCU) performance of MgB2O4 (B=Cr, Ga, Fe, Al)/CaCe15 was conducted. Results show that MgCr2O4/CaCe15 demonstrates exceptional performance, with CO2 uptake capacity, CO2 conversion, ethane conversion, ethylene selectivity, and ethylene yield after multiple cycles measuring at 0.22 g/g, 35.6%, 19.6%, 89%, and 17.4%, respectively. The dominant mechanism during the CO2 utilization stage was explored, and the coupling mechanism of catalytic dehydrogenation and reverse water-gas shift reaction is dominant, with abundant acid and basic sites within MgCr2O4/CaCe15 contributing to its outstanding performance. The reaction pathway during CO2 utilization was investigated, and results show that hydrogenation activation (CO2*+H*→HCOO*→CO*+OH*) is the primary pathway for CO2 dissociation, with the oxidative dehydrogenation of ethane mainly attributed to the activation of C-H on distinct C atoms, CH3CH3*→CH3CH2*→CH2CH2*. Meanwhile, the scission of the first C-H bond during CO2 utilization is the rate-determining step. Furthermore, we investigated the influencing factors and discovered that increasing the concentration of ethane and weight hourly space velocity both lead to a decrease in ethylene yield. © 2023, The Authors. All rights reserved.

关键词： Carbon dioxide

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Research on Key Geographic Factors Affecting Lightning Tripping Based on Association Rules and Entropy Weight 4

Research on Key Geographic Factors Affecting Lightning Tripp...

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4th IEEE China International Electrical and Energy Conference, CIEEC 2021

作者： Pang, Songling Zhang, Dandan Yang, Liguo Wei, Shixun Zhao, Hailong Pan, Wenwu Electric Power Science Research Institute of Hainan Power Grid Co. Ltd. Hainan Power Grid Tropical Smart Grid Laboratory Haikou China Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan China

ISBN: (纸本)9781728171494

Lightning is one of the important causes of transmission line tripping. In order to improve the effectiveness of transmission line risk assessment and provide reference for lightning protection design, it is necessary to study the key geographical factors affecting lightning tripping. In this paper, firstly, the geographical features such as altitude, slope, slope aspect, slope position and land type of the tower are extracted by using ArcGIS geographic software, and then the association rules are used to study the relationship between various geographical factors and lightning tripping. Finally, the entropy method is used to calculate the weight of various geographical factors on lightning tripping and determine the key factors. After calculation, the influence weight of slope on lightning tripping is 0.49, which accounts for the largest weight among geographical factors, so the influence of slope on lightning tripping should be considered in lightning protection design. © 2021 IEEE.

关键词： Association rules

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Short-Circuit Current Calculation Method for Power System with Renewable Energy Source and HVDC System

Short-Circuit Current Calculation Method for Power System wi...

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IEEE Conference on Energy Internet and Energy System Integration (EI2)

作者： Yuxi Wang Kun Qian Minghao Wen State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

ISBN: (纸本)9781665434263

The short-circuit currents characteristics of renewable energy source (RES) and high voltage direct current (HVDC) system are different from the short-circuit currents characteristics of traditional synchronous generator (SG). According to the fault-ride-through (FRT) requirements of different types of RES, the steady-state short-circuit currents calculation models of doubly-fed induction generator (DFIG) and inverter-interface renewable energy source (IIRES) such as photovoltaic (PV) and direct-drive permanent magnetic synchronous generator (D-PMSG) are built in this paper. Based on the converter switching function model and the HVDC control system, the calculation model of HVDC system steady-state short-circuit currents is built. Combined with RES and HVDC system short-circuit currents calculation models, a short-circuit currents calculation method for power system with multiple types RES and HVDC under ac power system fault is proposed. Finally, the effectiveness of the proposed method of short-circuit currents calculation is verified by simulation cases.

关键词： Renewable energy sources Short-circuit currents HVDC transmission Doubly fed induction generators System integration Synchronous generators Mathematical models

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Self-confocal NIR-II fluorescence microscopy for multifunctional in vivo imaging

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Journal of Innovative Optical Health Sciences 2024年第1期17卷 105-119页

作者： Jing Zhou Tianxiang Wu Runze Chen Liang Zhu Hequn Zhang Yifei Li Liying Chen Jun Qian State Key Laboratory of Modern Optical Instrumentations Centre for Optical and Electromagnetic ResearchCollege of Optical Science and EngineeringInternational Research Center for Advanced PhotonicsZhejiang UniversityHangzhou 310058P.R.China Dr.Li Dak Sum&Yip Yio Chin Center for Stem Cell and Regenerative Medicine Zhejiang UniversityHangzhou 310058P.R.China College of Biomedical Engineering and Instrument Science Interdisciplinary Institute of Neuroscience and Technology(ZIINT)Zhejiang UniversityHangzhou 310027P.R.China

Fluorescence imaging in the second near-infrared window(NIR-II,900–1880 nm)with less scattering background in biological tissues has been combined with the confocal microscopic system for achieving deep in vivo imaging with high spatial ***,the traditional NIR-IIfluorescence confocal microscope with separate excitation focus and detection pinhole makes it possess low confocal e±ciency,as well as di±cultly to *** types of upgraded NIR-IIfluorescence confocal microscopes,sharing the same pinhole by excitation and emission focus,leading to higher confocal e±ciency,are built in this *** type is-ber-pinhole-based confocal microscope applicable to CW laser *** is constructed forfluorescence intensity imaging with large depth,high stabilization and low cost,which could replace multiphotonfluorescence microscopy in some applications(e.g.,cerebrovascular and hepatocellular imaging).The other type is air-pinhole-based confocal microscope applicable to femtosecond(fs)laser *** can be employed not only for NIR-IIfluorescence intensity imaging,but also for multi-channelfluorescence lifetime imaging to recognize different structures with similarfluorescence ***,it can be facilely combined with multiphotonfluorescence microscopy.A single fs pulsed laser is utilized to achieve up-conversion(visible multiphotonfluorescence)and down-conversion(NIR-II one-photonfluorescence)excitation simultaneously,extending imaging spectral channels,and thus facilitates multi-structure and multi-functional observation.

关键词： Self-confocal fiber-pinhole air-pinhole multi-channe fluorescence lifetime imaging multi-color imaging

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Ball Mill Fault Prediction Based on Deep Convolutional Auto-Encoding Network

arXiv

引用

arXiv 2023年

作者： Ai, Xinkun Liu, Kun Zheng, Wei Fan, Yonggang G. Wu, Xinwu Zhang, Peilong Wang, LiYe Zhu, JanFeng Pan, Yuan State Key Laboratory of Advanced Electromagnetic Technology International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan430074 China Wugang Resources Group Co. Ltd. Ezhou436000 China

Ball mills play a critical role in modern mining operations, making their bearing failures a significant concern due to the potential loss of production efficiency and economic consequences. This paper presents an anomaly detection method based on Deep Convolutional Auto-encoding Neural Networks (DCAN) for addressing the issue of ball mill bearing fault detection. The proposed approach leverages vibration data collected during normal operation for training, overcoming challenges such as labeling issues and data imbalance often encountered in supervised learning methods. DCAN includes the modules of convolutional feature extraction and transposed convolutional feature reconstruction, demonstrating exceptional capabilities in signal processing and feature extraction. Additionally, the paper describes the practical deployment of the DCAN-based anomaly detection model for bearing fault detection, utilizing data from the ball mill bearings of Wuhan Iron & Steel Resources Group and fault data from NASA's bearing vibration dataset. Experimental results validate the DCAN model's reliability in recognizing fault vibration patterns. This method holds promise for enhancing bearing fault detection efficiency, reducing production interruptions, and lowering maintenance costs. Copyright © 2023, The Authors. All rights reserved.

关键词： Feature extraction

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Formation of quasi-single helicity state from a paramagnetic pinch in KTX regime

arXiv

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arXiv 2024年

作者： Luo, Bing Zhu, Ping Yan, Wentan Li, Hong Liu, Wandong Hunan Province Key Laboratory Integration and Optical Manufacturing Technology College of Mathematics and Physics Hunan University of Arts and Science Hunan Changde415000 China International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Hubei Wuhan430074 China Department of Nuclear Engineering and Engineering Physics University of Wisconsin-Madison MadisonWI53706 United States School of Nuclear Science and Technology University of Science and Technology of China Anhui Hefei230026 China

The formation of quasi-single helicity (QSH) state from a paramagnetic pinch in the KTX-RFP regime has been observed in recent NIMROD simulations. The quasi-single helicity state has a dominant helical component of the magnetic field that is known to improve the RFP confinement. For the initial paramagnetic pinch, linear calculations indicate that the tearing mode growth rate decreases with the plasma β. The initial QSH state arises from the dominant linear instability of the initial force-free paramagnetic pinch. The plasma’s self-organization towards the second QSH state after the relaxation of the initial QSH state is found to depend on β. Specifically, when β Copyright © 2024, The Authors. All rights reserved.

关键词： Paramagnetism

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Research on the Variation of Lightning Activity Parameters with Land Types Based on Lightning Location System 4

Research on the Variation of Lightning Activity Parameters w...

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4th IEEE China International Electrical and Energy Conference, CIEEC 2021

作者： Han, Wuqi Zhang, Dandan Zhao, Hailong Wei, Shixun Pang, Songling Pan, Wenwu Electric Power Science Research Institute of Hainan Power Grid Co. Ltd. Hainan Power Grid Tropical Smart Grid Laboratory Haikou China Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology Wuhan China

ISBN: (纸本)9781728171494

The statistics of lightning activity parameters is the basis to guide the lightning protection design, transformation and study of lightning characteristics of transmission lines. The lightning activity parameters are closely related to the land type. Based on the ground lightning data of lightning location system in Hainan Island, combined with the land type data from resource and environmental science and data center, this paper uses ArcGIS geographic software to supplement the land type data of ground flash point, and studies the law of lightning activity parameters and land types, such as mean value of lightning current amplitude, ground lightning density, cumulative probability distribution of lightning current amplitude, positive lightning ratio and so on. The study shows that the average amplitude of total lightning current in paddy field is the largest;due to the heat island effect, the total land flash density, negative ground flash density and positive ground flash density of urban land are much higher than those of other land types, and more attention should be paid to the transformation of forest land lightning protection measures;the median current of cultivated land is the largest, and the probability of larger amplitude lightning current is the largest. The proportion of positive flashover in lakes is the largest, so the influence of positive lightning on lightning shielding of transmission lines should be properly considered. © 2021 IEEE.

关键词： Electric lines

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