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Diagnosis of Disc Space Variation Fault Degree of Transformer Winding Based on K-Nearest Neighbor Algorithm

Energy Engineering 2023年第10期120卷 2273-2285页

作者： Song Wang Fei Xie Fengye Yang Shengxuan Qiu Chuang Liu Tong Li Department of Power and electrical Engineering Northwest A&F UniversityYangling712100China NARI Group Beijing Kedong Electric Power Control System Co.Ltd.Beijing100000China Huangling Mining Group co. Ltd.Shanxi Coal and Chemical Industry GroupHuangling716000China

Winding is one of themost important co.ponents in power *** the health state of the winding is of great importance to the stable operation of the power *** efficiently and accurately diagnose the disc space variation(DSV)fault degree of transformer winding,this paper presents a diagnostic method of winding fault based on the K-Nearest Neighbor(KNN)algorithmand the frequency response analysis(FRA)***,a laboratory winding model is used,and DSV faults with four different degrees are achieved by changing disc space of the discs in the ***,a series of FRA tests are co.ducted to obtain the FRA results and set up the FRA ***,ten different numerical indices are utilized to obtain features of FRA curves of faulted ***,the 10-fold cross-validation method is employed to determine the optimal k-value of *** addition,to improve the accuracy of the KNN model,a co.parative analysis is made between the accuracy of the KNN algorithm and k-value under four distance *** getting the most appropriate distance metric and kvalue,the fault classificationmodel based on theKNN and FRA is co.structed and it is used to classify the degrees of DSV *** identification accuracy rate of the proposed model is up to 98.30%.Finally,the performance of the model is presented by co.paring with the support vector machine(SVM),SVM optimized by the particle swarmoptimization(PSO-SVM)method,and randomforest(RF).The results show that the diagnosis accuracy of the proposed model is the highest and the model can be used to accurately diagnose the DSV fault degrees of the winding.

关键词： Transformer winding frequency response analysis(FRA)method K-Nearest Neighbor(KNN) disc space variation(DSV)

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Ambient formaldehyde co.centrations in summer in 30 Chinese cities and impacts on air cleaning of built environment

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Energy and Built Environment 2024年第4期5卷 493-499页

作者： Shuolin Qiu Zirui He Guangdong Liu Zhen Ding Zhongming Bu Jianping Cao Wenjing Ji Wei Liu Chunxiao Su Xinke Wang Fan Liu Ting Li Hua Qian co.g Liu School of Energy and Environment Southeast UniversityNanjingJiangsu210096China China Green Development Investment Group co.ltd Beijing100000China Department of Environmental Health Jiangsu Provincial Center for Disease Control and PreventionNanjingJiangsu210009China Department of Energy and Environmental system Engineering Zhejiang University of Science and TechnologyHangzhouZhejiang310023China School of Environmental Science and Engineering Sun Yat-sen UniversityGuangzhouGuangdong510006China School of Civil and Resource Engineering University of Science and Technology BeijingBeijing100083China Institute for Health and Environment Chongqing University of Science and TechnologyChongqing401331China School of Environment and Architecture University of Shanghai for Science and TechnologyShanghai200093China School of Human Settlements and Civil Engineering Xi’an Jiaotong UniversityXi’an710049ShaanxiChina Tsinghua University Beijing100084China

Formaldehyde is an important carcinogen co.monly found *** indoor sources have been intensively *** study on outdoor formaldehyde co.centration,which is potentially an important source to indoors,remains *** study attempts to characterize temporal and spatial distribution of the atmospheric formalde-hyde co.centration in Chinese *** variation of ambient formaldehyde was examined in 6 cities and peak hours were identified between 12:00 pm and 3:00 ***,outdoor formaldehyde co.centrations were measured in the peak hours in 30 cities during the summer months of Jul.-Aug.,*** formaldehyde co.centrations in the peak hours fell into a range of 0.005-0.087 mg/m^(3)(median value is 0.027 mg/m^(3)),87.7%of which have exceeded the chronic reference exposure criteria of 0.009 mg/m^(3) set by Office of Environmental Health Hazard *** risk analysis suggests that exposure to ambient formaldehyde co.ld cause a median carcinogenic risk of 1.9×10^(−5)(3.17×10^(−6)-6.13×10^(−5)),higher than threshold limit of 10−*** co.relation analysis of the 30 cities shows that ambient summertime atmospheric formaldehyde co.centrations of the city are positively co.related with its Gross Domestic Product(r=0.48).We also found that the outdoor formaldehyde co.centrations in urban areas(median:0.017 mg/m^(3))is slightly higher than those in suburban areas(median:0.013 mg/m^(3)).Results here prove that outdoor formaldehyde is ubiquitous in Chinese cities and reduces effectiveness of ventilation in dilution indoor *** it would underestimate air cleaner capacity needed by a factor of about *** should be acco.nted for in health analysis and air quality engineering control design of built environment in the future.

关键词： Atmospheric formaldehyde Temporal distribution Health risk Ventilation efficiency

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Active Dynamic Aggregation Model for Distributed Integrated Energy system as Virtual Power Plant

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Journal of Modern Power systems and Clean Energy 2020年第5期8卷 831-840页

作者： Haotian Zhao Bin Wang Xuanyuan Wang Zhaoguang Pan Hongbin Sun Zhen Liu Qinglai Guo State Key Laboratory of control and Simulation of Power system and Generation Equipments Department of Electrical EngineeringTsinghua UniversityBeijingChina State Grid Jibei electric Power co. Ltd.BeijingChina

Distributed integrated multi-energy systems(DIMSs)can be regarded as virtual power plants to provide additional flexibility to the power *** paper proposes a robust active dynamic aggregation model for the DIMSs to describe the maximum feasible *** aggregation model includes the power co.straints,energy co.straints,and ramping co.straints to aggregate different types of resources in the *** proposed generator-like and storage-like model does not depend on the ancillary service market and can be directly inco.porated into the eco.omic dispatch model of the power system.A novel algorithm based on the co.umn-and-co.straint generation algorithm and co.vex-co.cave procedure is proposed to solve the two-stage robust optimization problem,which is more efficient than the KKT-based ***,a case study of an actual DIMS is developed to demonstrate the effectiveness of the proposed model.

关键词： Aggregation distributed integrated energy system(DIMS) robust optimization virtual power plant

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Area-based non-maximum suppression algorithm for multi-object fault detection

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Frontiers of Optoelectronics 2020年第4期13卷 425-432页

作者： Jieyin BAI Jie ZHU Rui ZHAO Fengqiang GU Jiao WANG Nanrui Group co. Ltd.Beijing 100192China State Grid beijing electric Power co.pany Beijing 100031China beijing kedong electric Power control system co. Ltd.Beijing 100192China

Unmanned aerial vehicle(UAV)photography has beco.e the main power system inspection method;however,automated fault detection remains a major *** algorithms enco.nter difficulty in processing all the detected objects in the power transmission lines *** object detection method involving deep learning provides a new method for fault ***,the traditional non-maximum suppression(NMS)algorithm fails to delete redundant annotations when dealing with objects having two labels such as insulators and *** this study,we propose an area-based non-maximum suppression(A-NMS)algorithm to solve the problem of one object having multiple *** A-NMS algorithm is used in the fusion stage of cropping detection to detect small *** prove that A-NMS and cropping detection achieve a mean average precision and recall of 88.58%and 91.23%,respectively,in case of the aerial image datasets and realize multi-object fault detection in aerial images.

关键词： fault detection area-based non-maximum suppression(A-NMS) cropping detection

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Analysis of the Gravity-1 Sea Launch system and Technical Features

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Aerospace China 2024年第1期25卷 18-27页

作者： ZHANG Tao HUANG Shuai Ma Ma BU Xiangwei XU Guoguang Orienspace Technology(Shandong)co. LtdBeijing 100076

Sea launch has the characteristics of flexible launching points, high landing area safety, and good eco.omy. In recent years, it has beco.e one of the important launch methods. Since 2019, China has carried out a total of 11 successful sea launches. The Gravity-1(YL-1) sea launch system co.sists of a launch vehicle system and a sea launch platform. The sea launch program includes roll on/roll off boarding, sea mooring, sea maneuvering, anchoring and positioning, system testing, and formal launch. Through the maiden flight of YL-1, the design and manufacturing technology of large tonnage dedicated launch ship, launch vehicle vertical transfer and roll on/roll off boarding technology, anti-shake technology for sea launch, simple inflatable flexible insulation protective co.er technology, and remote wireless measurement and control technology have been fully verified.

关键词： YL-1 sea launch system technical features

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Peracetic acid catalytic activation using co.O4 nanocluster deco.ated graphitic carbon nitride for cefapirin degradation in water

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Science China Technological Sciences 2024年第10期67卷 3103-3115页

作者： YIN ShiMei GAO YiXuan CHEN Long LI Fan LIU XiaoNa QI Fei LIU Wen beijing Key Lab for Source control Technology of Water Pollution College of Environmental Science and EngineeringBeijing Forestry University Key Laboratory of Water and Sediment Sciences (Ministry of Education) College of Environmental Sciences and EngineeringPeking University School of Environmental Science and Engineering Taiyuan University of Technology State Environmental Protection Key Laboratory of All Material Fluxes in River Eco.0}s Peking University beijing National Laboratory for Molecular Sciences Peking University

This study innovated co.alt-based catalytic nanoco.posites（CCNs） for the heterogeneous activation of peracetic acid（PAA）,a green and efficient advanced oxidation process for removing antibiotics from *** co.O4catalysts exhibit limited activity due to stable electronic *** overco.e this,CCNs were synthesized using a one-step co.densation method,inco.porating a size control strategy that anchors co.O4nanoclusters within 4-5 nm onto six-fold cavity of g-C3N4,simultaneously modifying the co.rdination environment of *** alteration significantly enhances the adsorption energy of PAA and catalytic activity co.pared to co.mercial *** improved performance of CCN2,in particular,is attributed to a shift in the co.alt d band center towards the Fermi level,facilitating electron delocalization and transfer,enhancing co.O bonding,and accelerating PAA ***2's superior activity,with a cefapirin（CFP） degradation kinetic rate co.stant(k1=0.760 min-1)～11 times that of PAA direct oxidation(k1=0.070 min-1) and～5 times that of co.mercial co.O4/PAA system(k1=0.164 min-1),is due to its ability to generate dominant reactive species for antibiotic degradation,including alkoxy radicals(CH3C（=O）OO·),high valence metal(co.（=O）2+),and singlet oxygen（1O2）,with the latter two being crucial for the degradation *** degradation of CFP involved three mechanisms,including direct oxidation by PAA,decarboxylation,and open-ring reactions at nitrogen *** research provides insights into developing high-activity catalysts for efficient PAA activation and antibiotic removal,leveraging the strategy of shifting the transition metal d band center.

关键词： peracetic acid co.O4 nanocluster high valence metal singlet oxygen cefapirin

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Solid Rocket Booster Thrust Asynchrony Identification Method for Solid Rocket Bundled Rockets With ESO

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Aerospace China 2024年第1期25卷 40-46页

作者： WU Kao ZHANG Chi CHEN Yan XU Guoguang BU Xiangwei Oriental Space Technology(Shandong)co. LtdBeijing 102600

The role of the rocket attitude control system is to execute the required maneuvers for guidance and ensure the stability of the rocket's flight attitude. Attitude control technology has always been one of the key technologies for ensuring the success of rocket flights and has been a co.e topic in carrier rocket technology research. The Gravity-1 solid carrier rocket is the first solid rocket bundled rocket developed by China, adopting a co.figuration with four boosters and a co.e stage bundled together. During the actual flight process, the four booster engines are ignited first, and then, in the event of insufficient control force from the boosters, the co.e stage engine is ignited to participate in control. To address thrust asynchrony during the descent of the four boosters, an Extended State Observer(ESO) is employed in the control scheme for this flight segment. This involves real-time estimation and co.pensation of attitude parameters during flight, identification of thrust asynchrony among the boosters, and simultaneous determination of whether the co.e stage engine is ignited to participate in *** six degrees of freedom simulation analysis and Y1 flight test validation, this method has been proven to be co.rect and feasible.

关键词： Extended State Observer(ESO) solid booster attitude control thrust asynchrony

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Research on fault time prediction method for high speed rail BTM unit based on multi method interactive validation

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High-Speed Railway 2024年第3期2卷 164-171页

作者： Limin Fu Junqiang Gou Chao Sun Hanrui Li Wei Liu School of Information Science and Technology Southwest Jiaotong UniversityChengdu 611756China China Railway Signal and co.munication Research and Design Institute Group co.ltd. Beijing 100089China

The Balise Transmission Module(BTM)unit of the on-board train control system is a crucial *** to its unique installation position and co.plex environment,this unit has a higher fault rate within the on-board train control *** co.duct fault prediction for the BTM unit based on actual fault data,this study proposes a prediction method co.bining reliability statistics and machine learning,and achieves the fusion of prediction results from different dimensions through multi-method interactive ***,a method for predicting equipment fault time targeting batch equipment is *** method utilizes reliability statistics to co.struct a model of the remaining faultless operating time distribution co.sidering uncertainty,thereby predicting the remaining faultless operating probability of the BTM ***,co.sidering the co.plexity of the BTM unit’s fault mechanism,the small sample size of fault cases,and the potential presence of multiple fault features in fault text reco.ds,an individual-oriented fault prediction method based on Bayesian-optimized Gradient Boosting Regression Tree(Bayes-GBRT)is *** method achieves better prediction results co.pared to linear regression algorithms and random forest regression algorithms,with an average absolute error of only 0.224 years for predicting the fault time of this type of ***,a multi-method interactive validation approach is proposed,enabling the fusion and validation of multi-dimensional *** results indicate that the predicted fault time and the actual fault time co.form to a log-normal distribution,and the parameter estimation results are basically co.sistent,verifying the accuracy and effectiveness of the prediction *** above research findings can provide technical support for the maintenance and modification of BTM units,effectively reducing maintenance co.ts and ensuring the safe operation of high-speed railway,thus having practical engineering va

关键词： High speed rail BTM unit Remaining faultless operating time Machine learning Multi method interactive verification

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co.ID-19 transmission and control in land public transport:A literature review

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Fundamental Research 2024年第3期4卷 417-429页

作者： Qiqi Luo Wenbing Liu Jiayuan Liao Zhongli Gu Xiaodan Fan Zhiwen Luo Xuelin Zhang Jian Hang Cuiyun Ou School of Atmospheric Sciences Sun Yat-sen Universityand Southern Marine Science and Engineering Guangdong LaboratoryZhuhai 519082China Key Laboratory of Urban Meteorology China Meteorological AdministrationBeijing 100089China China Meteorological Administration Xiong'an Atmospheric Boundary Layer Key Laboratory Xiong'an 070001China Key Laboratory of Tropical Atmosphere-Ocean system(Sun Yat-sen University) Ministry of EducationZhuhai 519000China Guangdong Fans-tech Agro co. LtdYunfu 527300China Welsh School of Architecture Cardiff UniversityCardiff CF103XQUnited Kingdom

Land public transport is an important link within and between cities,and how to control the transmission of co.ID-19 in land public transport is a critical issue in our daily ***,there are still many inco.sistent opinions and views about the spread of SARS-co.-2 in land public transport,which limits our ability to implement effective *** purpose of this review is to overview the literature on transmission characteristics and routes of the epidemic in land public transport,as well as to investigate factors affecting its spread and provide feasible measures to mitigate the infection risk of *** obtained 898 papers by searching the Web of Science,Pubmed,and WHO global co.ID database by keywords,and finally selected 45 papers that can address the purpose of this *** public transport is a high outbreak area for co.ID-19 due to characteristics like crowding,inadequate ventilation,long exposure time,and environmental *** from surface touch transmission and drop spray transmission,aerosol inhalation transmission can occur not only in short distances but also in long *** ventilation is the most important factor influencing long-distance aerosol *** transmission factors(e.g.,interpersonal distance,relative orientation,and ambient co.ditions)should be noticed as well,which have been summarized in this *** address various influencing factors,it is essential to suggest practical and efficient preventive *** these,increased ventilation,particularly the fresh air(i.e.,natural ventilation),has proven to effectively reduce indoor infection *** preventive measures are also effective,such as enlarging social distance,avoiding face-to-face orientation,setting up physical partitions,disinfection,avoiding talking,and so *** research on the epidemic has intensified,people have broken down many perceived barriers,but more co.prehensive studies on monitoring systems and preventi

关键词： Land transportation Infection risk Transmission route Mitigation measures co.ID-19

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Integrated Distribution Management system:Architecture,Functions,and Application in China

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Journal of Modern Power systems and Clean Energy 2022年第2期10卷 245-258页

作者： Wenchuan Wu Penghua Li Bin Wang Yingshang Liu Tao Xu Hongwei Du Yan He the State Key Laboratory of Power systems Department of Electrical EngineeringTsinghua UniversityBeijing 100084China the electric Power control Center of China Southern Power Grid co.poration GuangzhouChina the National electric Power control Center of State Grid co.poration of China BeijingChina NARI Technology co. Ltd.NanjingChina beijing Guoke Hengtong Technology co. Ltd.BeijingChina

As massive distributed energy resources(DERs)are integrated into distribution networks(DNs)and the distribution automation facilities are widely deployed,the DNs are evolving to active distribution networks(ADNs).This paper introduces the architecture and main function modules of an integrated distribution management system(IDMS)and its applica-tions in *** system co.sists of three subsystems,including the real-time operation and control system(OCS),outage management system(OMS),and operator training simulator(OTS).The OCS has a hierarchical architecture with three levels,including the local controller for DER clusters,the optimization of DNs inco.porated with multi-clusters,and the co.rdina-tion operation of integrated transmission&distribution(T&D)*** OMS is developed based on the geographical information system(GIS)and co.rdinated with *** in the OTS,both the ADN and its host transmission network(TN)are simulated to make the simulation results more *** main functions of the three subsystems and their interaction data flows are described and some typical application scenarios are also presented.

关键词： Active distribution network(ADN) integrated distribution management system(IDMS) operation and control system(OCS) outage management system(OMS) operator training simulator(OTS) geographical information system(GIS).

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