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CSEE Journal of power and energy Systems 2024年第4期10卷 1642-1653页

作者： Zhi Geng Minxiao Han Changjiang Xia Longze Kou School of Electrical and Electronic Engineering North China Electric Power University(NCEPU)Beijing 102206China state key laboratory of advanced power transmission technology Global Energy Interconnection Research InstituteBeijing 102209China

Due to the large number of submodules(SMs),and modular multilevel co.verters(MMCs)in high-voltage applications,they are usually regulated by the nearest level modulation(NLM).Moreover,the large number of SMs causes a challenge for the fault diagnosis strategy(FDS).This paper proposes a currentless FDS for MMC with *** FDS,the voltage sensor is relocated to measure the output voltage of the *** acquire the capacitor voltage and avoid increasing extra sensors,a capacitor voltage calculation method is *** on the measurement of output voltages,the faults can be detected and the number of different-type switch open-circuit faults can be co.firmed from the numerous SMs in an arm,which narrows the sco.e of fault ***,the faulty SMs and faulty switches in these SMs are further located without arm current acco.ding to the sorting of capacitor voltages in the voltage balancing *** FDS is independent of the arm current,which can reduce the co.munication co.t in the hierarchical co.trol system of ***,the proposed FDS not only simplifies the identification of switch open-circuit faults by co.firming the sco.e of faults,but also detects and locates multiple different-type faults in an *** effectiveness of the proposed strategy is verified by the simulation results.

关键词： Fault diagnosis high voltage direct current(HVDC) modular multilevel co.verter(MMC) nearest level modulation(NLM) switch open-circuit fault

Fully Deco.pled Branch energy Balancing co.trol Method for Modular Multilevel Matrix co.verter Based on Sequence Circulating co.ponents

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CSEE Journal of power and energy Systems 2024年第1期10卷 235-247页

作者： Zexin Zhao Weijiang Chen Zhichang Yang Guoliang Zhao Bin Han Yunfei Xu Nianwen Xiang Shulai Wang China Electric power research institute Beijing 100192China state Grid co.poration of China Beijing 100031China state Grid Smart Grid research institute Beijing 102209China state key laboratory of advanced power transmission technology Global Energy Interconnection Research InstituteBeijing 102211China Hefei University of technology Hefei 230009China

The modular multilevel matrix co.verter(M3C)is a potential frequency co.verter for low-frequency AC ***,capacitor voltage co.trol of high-voltage and largecapacity M3C is more difficult,especially for voltage balancing between *** solve this problem,this paper defines sequence circulating co.ponents and theoretically analyzes the influence mechanism of different sequence circulating co.ponents on branch capacitor voltage.A fully deco.pled branch energy balancing co.trol method based on four groups of sequence circulating co.ponents is *** method can co.trol capacitor voltages of nine branches in horizontal,vertical and diagonal *** influences of both circulating current and voltage,a cross deco.pled co.trol is designed to improve co.trol *** results are taken from a low-frequency transmission system based on PSCAD/EMTDC,and effectiveness and precision of the proposed branch energy balancing co.trol method are verified in the case of nonuniform parameters and an unbalanced power system.

关键词： Branch energy balancing co.trol deco.pled co.trol low-frequency AC transmission modular multilevel matrix co.verter(M3C) sequence circulating co.ponents

advanced System-Level Model Reduction Method for Multi-co.verter DC power Systems

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CSEE Journal of power and energy Systems 2024年第4期10卷 1550-1562页

作者： Lin Zhu Xueshen Zhao Xialin Li Li Guo Bo Zhao Zhanfeng Deng Hao Lu Chengshan Wang the key laboratory of Smart Grid of Ministry of Education Tianjin UniversityTianjin 300072China the research institute of state Grid Zhejiang Electric power co. Ltd.Hangzhou 310014China the state Grid global energy interconnection research institute Beijing 102209China

For dynamic stability analysis and instability mechanism understanding of multi-co.verter medium voltage DC power systems with droop-based double-loop co.trol,an advanced system-level model reduction method is *** this method,mathematical relationships of co.trol parameters(e.g.,current and voltage co.trol parameters)between the system and its equivalent reduced-order model are ***,open-loop and closed-loop equivalent reduced-order models of current co.trol loop co.sidering dynamic interaction among co.verters are *** instability mechanism(e.g.,unreasonable current co.trol parameters)of the system can be revealed *** guidance for adjustment of current co.trol parameters can also be ***,co.sidering dynamic interaction of current co.trol among co.verters,open-loop and closed-loop equivalent reduced-order models of voltage co.trol loop are *** frequency and damping factor of DC bus voltage in a wide oscillation frequency range(e.g.,10–50 Hz)can be evaluated *** importantly,accuracy of advanced system-level model reduction method is not co.promised,even for MVDC power systems with inco.sistent co.trol parameters and different number of ***,experiments in RT-BOX hardware-in-the-loop experimental platform are co.ducted to validate the advanced system-level model reduction method.

关键词： Closed-loop reduced-order model instability mechanism open-loop reduced-order model stability analysis system-level model reduction method

Effective Ultra-High-Speed Identification Scheme of Lightning Strikes Suitable for VSC-Based DC Grids

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CSEE Journal of power and energy Systems 2024年第2期10卷 548-561页

作者： Longlong Chen Xiangyu Pei Xiaoguang Wei Pengzhi Li Guangfu Tang North China Electric power University(NCEPU) Beijing 102206China Changsha University of Science and technology Changsha 410114China state key laboratory of advanced power transmission technology State Grid Smart Grid Research Institute Co.Ltd.Beijing 102209China

To ensure their sound and co.tinuous operation to the greatest extent,VSC-based DC girds have extremely stringent requirements for transmission line relay *** terms of guaranteeing their reliability,accurate identification of lightning strikes on DC transmission lines is one of the urgent key problems to be *** effective ultra-high-speed identification scheme of lightning strikes suitable for the VSC-based DC grid is proposed in this ***,an 1-mode reverse voltage traveling wave(RVTW)is co.structed applying the pole-mode transformation ***,fault traveling wave propagation characteristics along the DC transmission line are analyzed in depth utilizing Peterson's ***,differences of time-frequency electromagnetic transient characteristics of 1-mode RVTWs between disturbances and faults caused by lightning strikes are distinguished in detail by means of the classical wavelet transformation multi-resolution analysis ***,extensive simulations are carried out to evaluate the performance of the proposed identification scheme,and by which its excellent rapidity,reliability and robustness are *** Terms-Lightning-strike identification,Multi-resolution analysis,Relay protection,Traveling-wave protection,VsC-based DC grid,Wavelet transformation.

关键词： Lightning-strike identification Multi-resolution analysis Relay protection Traveling-wave protection VsC-based DC grid Wavelet transformation

energy Blockchain in Smart co.munities: Towards Affordable Clean energy Supply for the Built Environment

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energy Engineering 2024年第8期121卷 2313-2330页

作者： Mingguan Zhao Lida Liao Penglong Liang Meng Li Xinsheng Dong Yang Yang Hongxia Wang Zhenhao Zhang Electric power research institute State Grid Xinjiang Electric Power Co.Ltd.Urumqi830013China School of energy and power Engineering Changsha University of Science&TechnologyChangsha410114China Kumul power Supply co.pany State Grid Xinjiang Electric Power Co.Ltd.Urumqi830013China Xinjiang key laboratory of Extreme Environment Operation and Detection technology of power transmission&Transformation Equipment Urumqi830013China

The rapid growth of distributed renewable energy penetration is promoting the evolution of the energy system toward decentralization and decentralized and digitized smart *** study was based on energy blockchain,and developed a dual-biding mechanism based on the real-time energy surplus and demand in the local smart grid,which is expected to enable reliable,affordable,and clean energy supply in smart *** the proposed system,eco.omic benefits co.ld be achieved by replacing fossil-fuel-based electricity with the high penetration of affordable solar PV *** reduction of energy surplus realized by distributed energy production and P2P energy trading,within the smart grid results in less transmission loss and lower requirements for co.tly upgrading of existing *** adopting energy blockchain and smart co.tract technologies,energy secure trading with a low risk of privacy leakage co.ld be *** prototype is examined through a case study,and the feasibility and efficiency of the proposed mechanism are further validated by scenario analysis.

关键词： Solar PV smart co.munity energy blockchain P2P energy trading smart grid affordable energy supply

Characterization of local chemical ordering and deformation behavior in high entropy alloys by transmission electron microsco.y

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International Journal of Minerals,Metallurgy and Materials 2024年第5期31卷 877-886页

作者： Qiuhong Liu Qing Du Xiaobin Zhang Yuan Wu Andrey A.Rempel Xiangyang Peng Xiongjun Liu Hui Wang Wenli Song Zhaoping Lü Beijing advanced Innovation Center for Materials Genome Engineering State Key Laboratory for Advanced Metals and MaterialsUniversity of Science and Technology BeijingBeijing 100083China School of Materials Science and Engineering Ocean University of ChinaQingdao 266100China institute of Metallurgy of the Ural Branch of the Russian Academy of Sciences Ekaterinburg 620016Russia China Nuclear power technology research institute co.Ltd. Shenzhen 518000China institute of High energy Physics Chinese Academy of Sciences(CAS)Beijing 100049China Spallation Neutron Source Science Center Dongguan 523803China

Short-range ordering(SRO)is one of the most important structural features of high entropy alloys(HEAs).However,the chemical and structural analyses of SROs are very difficult due to their small size,co.plexed co.positions,and varied *** electron microsco.y(TEM)as well as its aberration co.rection techniques are powerful for characterizing SROs in these co.positionally co.plex *** this short co.munication,we summarized recent progresses regarding characterization of SROs using TEM in the field of *** using advanced TEM techniques,not only the existence of SROs was co.firmed,but also the effect of SROs on the deformation mechanism was ***,the perspective related to application of TEM techniques in HEAs are also discussed.

关键词： high entropy alloys transmission electron microsco.y short-range ordering deformation mechanisms

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Regulated reaction pathway of co. photoreduction into CH4 by metal atom pair sites

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Rare Metals 2024年第9期43卷 4620-4627页

作者： Dong-Po He Guang-Bing Huang Jun Hu Yang Wu Xiao-Dong Li Qing-Xia Chen Shan Zhu Wen-Sheng Yan Jun-Fa Zhu Yang Pan Xing-Chen Jiao key laboratory of Synthetic and Biological co.loids Ministry of EducationSchool of Chemical and Material EngineeringJiangnan University Hefei National research Center for Physical Sciences at Microscale National Synchrotron Radiation LaboratoryUniversity of Science and Technology of China Max Planck institute of Microstructure Physics state Grid Anhui Electric power research institute

The carbon dioxide （co.） reduction process involves co.plex protonation, making the resulting product often unpredictable. To achieve the desired product, it is crucial to manipulate the reaction steps. Herein, we build the metal atom pair sites for selective co.photoreduction into methane. As a prototype, Ni atom pair sites loaded on the Mo S2nanosheets were synthesized and verified by highresolution transmission electron microsco.y （HRTEM）,X-ray photoelectron spectrosco.y （XPS） and X-rayabsorption near edge structure spectra （XANES）. In-situ Fourier transform infrared spectrosco.y （FTIR） monitors the*CHO group, a crucial intermediate in CH4production,during co.photoreduction on the Ni-Mo S2nanosheets,whereas this monitoring is not observed for the Mo S2nanosheets. Also, theoretical calculations disclose that over the Ni-Mo S2nanosheet slab, the formation energy of*CHO intermediates is determined to be lower （0.585 e V） than the desorption energy of*co.intermediates for co.production（0.64 e V）, implying the higher selectivity of CH4production. Acco.dingly, the Ni-Mo S2nanosheets demonstrate a methane formation rate of 27.21μmol·g-1·h-1, co.pled with an impressive electron selectivity of 94.2%.

关键词： Nanosheets

Optimal decision-making method for equipment maintenance to enhance the resilience of power digital twin system under extreme disaster

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global energy interconnection 2024年第3期7卷 336-346页

作者： Song Gao Wei Wang Jingyi Chen Xinyu Wu Junyan Shao Electric power Scientific research institute State Grid Jilin Electric Power CoLtdChangchun132000P.R.China Department of Electrical Engineering Northeast Electric Power UniversityJilin132012P.R.China

Digital twins and the physical assets of electric power systems face the potential risk of data loss and monitoring failures owing to catastrophic events,causing surveillance and energy *** study aims to refine maintenance strategies for the monitoring of an electric power digital twin system post ***,the research delineates the physical electric power system along with its digital co.nterpart and post-disaster restoration ***,it delves into co.munication and data processing mechanisms,specifically focusing on central data processing(CDP),co.munication routers(CRs),and phasor measurement units(PMUs),to re-establish an equipment reco.ery model based on these data transmission ***,it introduces a mathematical optimization model designed to enhance the digital twin system’s post-disaster monitoring efficacy by employing the branch-and-bound method for its *** efficacy of the proposed model was co.roborated by analyzing an IEEE-14 *** findings suggest that the proposed branch-and-bound algorithm significantly augments the observational capabilities of a power system with limited resources,thereby bolstering its stability and emergency response mechanisms.

关键词： Phasor measurement units Through-sequence optimization Resilience enhancement co.munication networks Digital twins

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Solute clusters-promoted strength-ductility synergy in Al-Sc alloy

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Journal of Materials Science & technology 2022年第1期96卷 325-331页

作者： Chong Yang Pengming Cheng Baoan Chen Jinyu Zhang Gang Liu Jun Sun state key laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049China state key laboratory of advanced power transmission technology Global Energy Interconnection Research Institute Co.Ltd.Beijing 102209China

Sc solute clusters with a high number density were produced in an Al-0.3 wt.%Sc alloy when aged at250℃,while fine Al_(3)Sc precipitates were predominantly formed in the same alloy aged at 300℃.The alloy strengthened by Sc solute clusters displayed higher yield strength and simultaneously greater ductility than its co.nterpart strengthened by Al_(3)Sc *** clearly demonstrates a superior strengthductility synergy promoted by the Sc solute clusters in Al-Sc *** effects of Al_(3)Sc precipitates and Sc solute clusters on ductility were discussed in co.parison by using a micromechanics fracture *** the Sc clusters were stabilized at 250℃,the Al-Sc alloys strengthened by Sc solute clusters should find extensive application fields within a wide temperature range,due to their high temperature resistance.

关键词： Al-Sc alloy Solute clusters Strength Ductility Micromechanics model

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The effect of a co.ductive polyaniline/carbon black co.posite on the performance of a semico.ductive layer

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High Voltage 2022年第2期7卷 233-241页

作者： Enmin Wang Sheng Zhang Ciyao Wang Shumei Chen Chuncheng Hao Qingquan Lei institute of advanced Electrical Materials Qingdao University of Science and TechnologyQingdaoChina state key laboratory of advanced power transmission technology(global energy interconnection research institute co. Ltd.)BeijingChina

In this study,co.ductive polyaniline(PANI)ribbons were introduced to a semi-co.ductive layer to improve the co.ductivity stability of the layer during thermal expansion and enhance its ability to inhibit charge injection into the insulating *** maximise the effect of PANI,PANI and carbon black(CB)were preformed into a uniformly dispersed co.posite,which was then added to the polymer matrix of the semico.ductive *** experimental results show that the resistivity of the semi-co.ductive layer co.taining the PANI/CB co.posite is more stable during thermal expansion than that of the semico.ductive layer only doped with *** is attributed to the co.ductive CB network being enhanced by the PANI *** addition,due to the unique co.ductivity mechanism and high dielectric co.stant of PANI,the semico.ductive layer has a strong ability to inhibit space charge injection into the insulating layer.

关键词： co.posite co.ductive layer