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Vibration and noise mechanism of a 110 kV transformer under DC bias based on finite element method

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Global Energy Interconnection 2024年第4期7卷 503-512页

作者： Ziyang Li Xujun Lang Bo Yang Xiaolin Liu Hao Wang Zhang Li shandong electric power engineering consulting institute Co. Ltd.Jinan 250013P.R.China School of electrical engineering Shandong UniversityJinan 250061P.R.China

Global energy and environmental issues are becoming increasingly problematic,and the vibration and noise problem of 110 kV transformers,which are the most widely distributed,have attracted widespread attention from both inside and outside the *** bias is one of the main contributing factors to vibration noise during the normal operation of *** clarify the vibration and noise mechanism of a 110 kV transformer under a DC bias,a multi-field coupling model of a 110 kV transformer was established using the finite element *** electromagnetic,vibration,and noise characteristics during the DC bias process were compared and quantified through field circuit coupling in parallel with the power frequency of AC,harmonic,and DC power *** was found that a DC bias can cause significant distortions in the magnetic flux density,force,and displacement distributions of the core and *** contributions of the DC bias effect to the core and winding are different at Kdc=*** this point,the core approached saturation,and the increase in the core force and displacement ***,the saturation of the core increased the leakage flux,and the stress and displacement of the winding increased *** sound field distribution characteristics of the 110 kV transformer under a DC bias are related to the force *** the DC bias coefficient was 1.25,the noise sound pressure level reached 73.6 dB.

关键词： Transformer DC bias Vibration Noise

Photon counting technique as a potential tool in micro-defect detection of epoxy insulation pull rod in gas-insulated switchgears

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High Voltage 2024年第2期9卷 267-274页

作者： Xianhao Fan Shu Niu Hanhua Luo Jizhong Liang Fang Liu Wenqiang Li Weidong Liu Wensheng Gao Yulong Huang Chuanyang Li Jinliang He School of electrical engineering Tsinghua UniversityBeijingChina electric power Research institute Shangxi Power Grid CorporationTaiyuanShanxiChina shandong Taikai electrical Insulation Co. Ltd.TaianShandongChina

The micro-defects in epoxy-based insulation materials generate a local high electric field which results in continuous degradation,seriously endangering the insulation system of gas-insulated switchgears.A highly sensitive detection technique is reported for micro-defects of insulation pull rods based on the photon counting(PC)*** re-sults demonstrated that for an epoxy-based insulation pull rod,the photons released during electroluminescence and ionisation at 2 kV,which is less than the partial discharge inception voltage,can be clearly *** findings presented a strong correlation between photon counts and defect *** has been conducted to elucidate the mechanism behind defect-induced PC,employing the amplification of ionising luminescence through electric field distortion induced by micro defects and the augmentation of electroluminescence through the aggregation of trap *** this regard,the authors verified that PC can serve as a potential tool in the detection of micro-insulation defects,which also has huge potential in online insulation condition monitoring.

关键词： technique. insulation defect

Optimal Location and Sizing ofMulti-Resource Distributed Generator Based onMulti-Objective Artificial Bee Colony Algorithm

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Energy engineering 2024年第2期121卷 499-521页

作者： Qiangfei Cao Huilai Wang Zijia Hui Lingyun Chen Economic and Technological Research institute State Grid Shanxi Electric Power Co.Ltd.Xi’an710075China Central Southern China electric power Design institute Co. Ltd.China Power Engineering Consulting GroupWuhan430074China

Distribution generation(DG)technology based on a variety of renewable energy technologies has developed rapidly.A large number of multi-type DG are connected to the distribution network(DN),resulting in a decline in the stability of DN *** is urgent to find a method that can effectively connect multi-energy DG to ***(PV),wind power generation(WPG),fuel cell(FC),and micro gas turbine(MGT)are considered in this paper.A multi-objective optimization model was established based on the life cycle cost(LCC)of DG,voltage quality,voltage fluctuation,system network loss,power deviation of the tie-line,DG pollution emission index,and meteorological index weight of ***-objective artificial bee colony algorithm(MOABC)was used to determine the optimal location and capacity of the four kinds of DG access DN,and compared with the other three heuristic *** tests based on IEEE 33 test node and IEEE 69 test node show that in IEEE 33 test node,the total voltage deviation,voltage fluctuation,and system network loss of DN decreased by 49.67%,7.47%and 48.12%,respectively,compared with that without DG *** the IEEE 69 test node,the total voltage deviation,voltage fluctuation and system network loss of DN in the MOABC configuration scheme decreased by 54.98%,35.93%and 75.17%,respectively,compared with that without DG configuration,indicating that MOABC can reasonably plan the capacity and location of *** the maximum trade-off between DG economy and DN operation stability.

关键词： Distributed generation distribution network life cycle cost multi-objective artificial bee colony algorithm voltage stability

Cu nanowire array with designed interphases enabling high performance Si anode toward flexible lithium-ion battery

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Nano Research 2024年第3期17卷 1516-1524页

作者： Pengfei Su Ziqi Zhang Linshan Luo Zhiyong Zhang Chaofei Lan Yahui Li Shaowen Xu Shanpeng Pei Guangyang Lin Cheng Li Xiang Han Wei Huang Songyan Chen Fujian Provincial Key Laboratory of Semiconductors and Applications Collaborative Innovation Center for Optoelectronic Semiconductors and Efficient DevicesDepartment of PhysicsXiamen UniversityXiamen 361005China College of Materials Science and engineering Nanjing Forestry UniversityNanjing 210037China Science and Technology on Analog Integrated Circuit Laboratory Chongqing 400060China shandong electric power engineering consulting institute Co. Ltd.Jinan 250013China

To meet the growing demand for wearable smart electronic devices,the development of flexible lithium-ion batteries(LIBs)is *** is an ideal candidate for the anode material of flexible lithium-ion batteries due to its high specific capacity,low working potential,and earth *** largest challenge in developing a flexible silicon anode is how to maintain structural integrity and ensure stable electrochemical reactions during external *** this work,we propose a novel design for fabricating core–shell electrodes based on a copper nanowire(CuNW)array core and magnetron sputtered Si/C *** nanowire array structure has characteristics of bending under longitudinal stress and twisting under transverse stress,which helps to maintain the mechanical stability of the structure during electrode bending and *** low-temperature annealing generates a small amount of Cu3Si alloy,which enhances the connection strength between Si and the conductive network and solves the poor conductivity problem of Si,which is known as a semiconductor *** unique configuration design of CuNW@Si@C-400℃ leads to stable long cycle performance of 1109 mAh∙g^(-1) after 1000 cycles and excellent rate performance of 500 mAh∙g^(-1) at a current density of 10 A∙g^(-1).Furthermore,the CuNW@Si@C-400℃||LiFePO_(4)(LFP)full battery demonstrates excellent flexibility,with a capacity retention of more than 96%after 100 *** study provides a promising strategy for the development of flexible lithium-ion batteries.

关键词： flexible lithium-ion battery silicon anode magnetron sputtering core–shell electrode Cu nanowire array

Research on ECMS Based on Segmented Path Braking Energy Recovery in a Fuel Cell Vehicle

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Energy engineering 2024年第1期121卷 95-110页

作者： Wen Sun Meijing Li Guoxiang Li Ke Sun Shuzhan Bai School of Energy and power engineering Shandong UniversityJinan250061China Automotive Research institute China National Heavy Duty Truck Group Co.Ltd.Jinan250061China

Proton exchange membrane fuel cells are widely regarded as having the potential to replace internal combustion engines in *** fuel cells cannot recover energy and have a slow dynamic response,they need to be used with different power *** efficient energy management strategies to achieve excellent fuel economy is the goal of *** paper proposes an adaptive equivalent fuel minimum consumption strategy(AECMS)to solve the problem of the poor economy of the whole vehicle caused by the wrong selection of equivalent factors(EF)in traditional *** this method,the kinematics interval is used to update the equivalent factor by considering the penalty term of energy recovery on SOC ***,the optimized equivalent factor is substituted into the optimization objective function to achieve efficient energy *** results under the New European Driving Cycle show that compared with the traditional ECMS based on fixed SOC benchmarks,the proposed method improves fuel economy by 1.7%while ensuring vehicle power and increases SOC by 30%.

关键词： Fuel cell PEMFC electric vehicle equivalent consumption minimization strategy

Evolutionary mechanism and frequency response of graphite electrode at extreme temperatures

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Nano Research 2024年第8期17卷 7283-7289页

作者： Shanpeng Pei Zhiyong Zhang Xiuli Zhang Yan Liu Xiang Han Linshan Luo Pengfei Su Chaofei Lan Wei Huang Ziqi Zhang Ming-Sheng Wang Songyan Chen Department of Physics Xiamen UniversityXiamen 361005China shandong electric power engineering consulting institute Corporation Jinan 250031China State Key Lab of Physical Chemistry of Solid Surfaces College of MaterialsXiamen UniversityXiamen 361005China School of Semiconductor Science and Technology South China Normal UniversityFoshan 528225China College of Materials Science and engineering Nanjing Forestry UniversityNanjing 210037China National Key Laboratory of Integrated Circuits and Microsystems Chongqing 400000China

The battery management system is employed to monitor the external temperature of the lithium-ion battery in order to detect any potential ***,this outside–in detection method often suffers from a lag and is therefore unable to accurately predict the battery’s real-time ***,an inside–out frequency response approach is used to accurately monitor the battery’s state at various temperatures in real-time and correlate it with the solid electrolyte interphase(SEI)evolution of the graphite *** SEI evolution at temperatures of−15,25,60,and 90℃exhibits certain regular characteristics with temperature *** a temperature of−15℃,the Li^(+)-solvent interaction of lithium-ion slowed down,resulting in a significant reduction in *** 25℃,a LiF-rich inorganic SEI was identified as forming,which facilitated lithium-ion ***,high temperatures would induce decomposition of lithium hexafluorophosphate(LiPF_(6))and lithium-ion *** the extreme temperature of 90℃,the SEI would be organic-rich,and Li_(x)P_(y)F_(z),a decomposition product of lithium salts,was further oxidized to Li_(x)PO_(y)F_(z),which led to a surge in the charge-transfer resistance at SEI(R_(sei))and a reduction in Coulombic efficiency(CE).This changing relationship can be recorded in real time from the inside out by electrochemical impedance spectroscopy(EIS)*** provides a new theoretical basis for the structural evolution of lithium-ion batteries and the regular characterization of EIS.

关键词： graphite electrode solid electrolyte interphase(SEI)film extreme temperatures frequency response evolutionary mechanism

Stability behavior of the Lanxi ancient flood control levee after reinforcement with upside-down hanging wells and grouting curtain

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Journal of Mountain Science 2024年第1期21卷 84-99页

作者： QIN Zipeng TIAN Yan GAO Siyuan ZHOU Jianfen HE Xiaohui HE Weizhong GAO Jingquan School of Water Conservancy and Environment engineering Zhejiang University of Water Resources and Electric PowerHangzhou 310018China Department of Civil engineering Imperial College LondonLondonSW71BFEngland Lanxi Water Affairs Bureau Lanxi 321102China Zhejiang Water Conservancy engineering consulting Co. LtdHangzhou 310051China

The stability of the ancient flood control levees is mainly influenced by water level fluctuations, groundwater concentration and rainfalls. This paper takes the Lanxi ancient levee as a research object to study the evolution laws of its seepage, displacement and stability before and after reinforcement with the upside-down hanging wells and grouting curtain through numerical simulation methods combined with experiments and observations. The study results indicate that the filled soil is less affected by water level fluctuations and groundwater concentration after reinforcement. A high groundwater level is detrimental to the levee's long-term stability, and the drainage issues need to be fully considered. The deformation of the reinforced levee is effectively controlled since the fill deformation is mainly borne by the upside-down hanging wells. The safety factors of the levee before reinforcement vary significantly with the water level. The minimum value of the safety factors is 0.886 during the water level decreasing period, indicating a very high risk of the instability. While it reached 1.478 after reinforcement, the stability of the ancient levee is improved by a large margin.

关键词： Stability analysis Multiple factors Antiseepage reinforcement Upside-down hanging well Grouting curtain Ancient levee

Entanglement quantification via weak measurements assisted by deep learning

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Photonics Research 2024年第4期12卷 712-719页

作者： MU YANG YA XIAO ZE-YAN HAO YU-WEI LIAO JIA-HE CAO KAI SUN EN-HUI WANG ZHENG-HAO LIU YUTAKA SHIKANO JIN-SHI XU CHUAN-FENG LI GUANG-CAN GUO CAS Key Laboratory of Quantum Information University of Science and Technology of ChinaHefei 230026China College of Physics and Optoelectronic engineering Ocean University of ChinaQingdao 266100China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei 230026China Hefei National Laboratory University of Science and Technology of ChinaHefei 230088China electric power Research institute State Grid Anhui Electric Power Co.Ltd.Hefei 230601China institute of Systems and Information engineering University of TsukubaIbaraki 305-8573Japan Center for Artificial Intelligence Research University of TsukubaIbaraki 305-8577Japan Graduate School of Science and Technology Gunma UniversityGunma 371-8510Japan institute for Quantum Studies Chapman UniversityOrangeCalifornia 92866USA JST PRESTO Saitama 332-0012Japan

Entanglement has been recognized as being crucial when implementing various quantum information ***, quantifying entanglement for an unknown quantum state requires nonphysical operations or post-processing measurement data. For example, evaluation methods via quantum state tomography require vast amounts of measurement data and likely estimation.

关键词： estimation quantum angle

Facile fabrication of graphene/g-C_(3)N_(4) for electromagnetic wave absorption

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Nano Research 2024年第3期17卷 1687-1698页

作者： Qiang Su Yunfei He Dongdong Liu Daguang Li Long Xia Xiaoxiao Huang Bo Zhong School of Materials Science and engineering Harbin Institute of Technology WeihaiWeihai 264209China Weihai Yunshan Technology Co. Ltd.Weihai 264200China State Key Laboratory on Integrated Optoelectronics College of Electronic Science&EngineeringJilin UniversityChangchun 130012China School of Materials Science and engineering Harbin Institute of TechnologyHarbin 150001China

With the development of the miniaturization of electronic equipment and lightweight weapon equipment,there are new requirements for electromagnetic wave absorption material(EMWAM).EMWAM has outstanding electromagnetic wave absorption properties and lightweight characteristics become an important direction of *** this study,graphene/g-C_(3)N_(4)(GGCN)EMWAM was first synthesized in situ by simple heat treatment,in which the g-C_(3)N_(4) had a porous structure and dispersed on the surface of *** impedance matching of the GGCN was well adjusted by decreasing the dielectric constant and attenuation constant due to the g-C_(3)N_(4) semiconductor property and the graphite-like *** EMW loss mechanism of GGCN was also analyzed by simulating GGCN’s electric field mode distribution and resistance loss power *** analysis result shows that the distribution of g-C_(3)N_(4) among GGCN sheets can produce more polarization effects and relaxation effects by increasing the lamellar ***,the polarization loss of GGCN could be increased successfully by porous g-C_(3)N_(4).Ultimately,the EMW absorption property of GGCN is optimized significantly,and GGCN exhibits excellent EMW absorption *** the thickness is 2 mm,the effective absorption bandwidth(EAB)can reach 4.6 GHz,and when the thickness is 4.5 mm,the minimum reflection loss(RLmin)at 4.56 GHz can reach-34.69 ***,the practical application of EMWAM was studied by radar cross-section(RCS)simulation,showing that GGCN has a good application prospect.

关键词： graphene/g-C_(3)N_(4) impedance matching simulation analysis dielectric loss excellent electromagnetic wave absorption