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Consideration of the influence of supports in modeling the electromagnetic fields of 25 kV traction networks under emergency conditions

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Global energy Interconnection 2024年第4期7卷 528-540页

作者： Konstantin Suslov Andrey Kryukov Ekaterina Voronina Pavel Ilyushin department of Hydropower and renewable energy National Research UniversityMoscow Power Engineering InstituteMoscow 11250Russia department of Power Supply and electrical Engineering Irkutsk National Research Technical UniversityIrkutsk 664074Russia department of transport Electric Power Irkutsk State Transport UniversityIrkutsk 664074Russia department of Research on the Relationship between energy and the Economy Energy Research Institute of the Russian Academy of SciencesMoscow 117186Russia

Single-phase 25 kV traction networks of electrified alternating current(AC)railways create electromagnetic fields(EMFs)with significant levels of *** most intense magnetic fields occur when short circuits exist between the contact wire and rails or *** the short duration of exposure,they can adversely affect electronic devices and induce significant voltages in adjacent power lines,which is dangerous for operating *** numerous investigations have focused on modeling the EMF of traction networks and power lines,the challenge of determining the three-dimensional electromagnetic fields near metal supports during the flow of a short-circuit current through them is yet to be *** this case,the field has a complex spatial structure that significantly complicates the calculations of *** study proposes a methodology,algorithms,software,and digital models for determining the EMF in the described emergency *** the modeling process,the objects being studied were represented by segments of thin wires to analyze the distribution of the electric charge and calculate the intensities of the electric and magnetic *** approach was implemented in the Fazonord software,and the modeling results show a substantial increase in EMF levels close to the support,with a noticeable decrease in the levels as the distance from it *** procedure implemented in the commercial software Fazonord is universal and can be used to determine electromagnetic fields at any electrical power facility that includes live parts of limited *** on the proposed procedure,the EMF near the supports of overhead power lines and traction networks of various designs could be determined,the EMF levels at substations can be calculated,and the influence of metal structures located near traction networks,such as pedestrian crossings at railway stations,can be considered.

关键词： Power supply systems AC railways Emergency conditions Electromagnetic fields near supports Modeling Electromagnetic safety

Superconducting energy storage technology-based synthetic inertia system control to enhance frequency dynamic performance in microgrids with high renewable penetration

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Protection and Control of Modern Power systems 2021年第1期6卷 460-472页

作者： Gaber Magdy Abualkasim Bakeer Mohammed Alhasheem electrical Engineering department Faculty of Energy EngineeringAswan UniversityAswan81528Egypt electrical Engineering department Faculty of EngineeringAswan UniversityAswan81542Egypt electrical Power Engineering and Mechatronics department School of EngineeringTallinn University of Technology19086TallinnEstonia department of electrical and Control Arab Academy for ScienceTechnologyand Maritime TransportCairo2033Egypt

With high penetration of renewable energy sources(RESs)in modern power systems,system frequency becomes more prone to fluctuation as RESs do not naturally have inertial properties.A conventional energy storage system(ESS)based on a battery has been used to tackle the shortage in system inertia but has low and short-term power support during the *** address the issues,this paper proposes a new synthetic inertia control(SIC)design with a superconducting magnetic energy storage(SMES)system to mimic the necessary inertia power and damping properties in a short time and thereby regulate the microgrid(µG)frequency during *** addition,system frequency deviation is reduced by employing the proportional-integral(PI)controller with the proposed SIC *** efficacy of the proposed SIC system is validated by comparison with the conventional ESS and SMES systems without using the PI controller,under various load/renewable perturbations,nonlinearities,and *** simulation results highlight that the proposed system with SMES can efficiently manage several disturbances and high system uncertainty compared to the conventional ESS and SMES systems,without using the PI controller.

关键词： Synthetic inertia control(SIC) Load frequency control(LFC) Superconducting magnetic energy storage(SMES) renewable energy sources(RESs) Microgrid(µG)

Driving pattern analysis of Nordic region based on National Travel Surveys for electric vehicle integration

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Journal of Modern Power systems and Clean energy 2015年第2期3卷 180-189页

作者： Zhaoxi LIU Qiuwei WU Linda CHRISTENSEN Antti RAUTIAINEN Yusheng XUE Centre for Electric Power and energy(CEE) Department of Electrical EngineeringTechnical University of DenmarkElektrovej 325Kgs.Lyngby 2800Denmark department of transport Technical University of DenmarkKgs.Lyngby 2800Denmark department of electrical Engineering Tampere University of TechnologyTampere 33101Finland State Grid Electric Power Research Institute Nanjing 210003China

Electic vehicles(EVs)show great potential to cope with the intermittency of renewable energy sources(RES)and provide demand side flexibility required by the smart ***,EVs will increase the electricity *** scale integration of EVs will probably have substantial impacts on power *** paper presents a methodology to transform driving behavior of person into one of the cars in order to analyze the driving pattern of EVs based on the National Travel *** the proposed methodology,a statistical process is used to obtain the driving behavior of cars by grouping the survey respondents according to the driving license number and car number,and mapping the households with similar *** proposed methodology was used to carry out the driving pattern analysis in the Nordic *** detailed driving requirements and charging/discharging availability of vehicles along the day were *** types of EV availabilities were studied in this paper considering different charging/discharging conditions of EVs for the power system integration,*** availability all day and EV availability at *** results show that the daily driving requirements of the Nordic region are not very *** driving patterns of vehicles in the Nordic region vary on weekdays and *** two types of EV availabilities are quite different from each other.

关键词： Driving pattern Electric vehicles(EVs) EV availability Nordic Power system integration

Carbon-neutral pathway to mitigating transport-power grid cross-sector effects

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The Innovation 2024年第3期5卷 27-29页

作者： Jing Ma Huiwen Kong Jianxiao Wang Haiwang Zhong Bo Li Jie Song Daniel M.Kammen State Key Laboratory of Alternate electrical Power System with renewable energy Sources School of Electrical and Electronic EngineeringNorth China Electric Power UniversityBeijing 102206China National Engineering Laboratory for Big Data Analysis and Applications Peking UniversityBeijing 100871China Peking University Ordos Research Institute of energy Ordos 017000China State Key Laboratory of Power systems and Generation Equipment Department of Electrical EngineeringTsinghua UniversityBeijing 100084China School of electrical Engineering Guangxi UniversityNanning 530004China department of Industrial Engineering and Management College of EngineeringPeking UniversityBeijing 100871China energy and Resources Group and Goldman School of Public PolicyUniversity of CaliforniaBerkeleyBerkeleyCA 94720USA

Dear Editor,The growing demand for transportation energy has brought increasing challenges to reducing greenhouse gas ***,many countries or regions have proposed solutions to achieve carbon-neutral transportation such as the rapid expansion of the global electric vehicle(EV)***,these benefits are not *** the goal of decarbonization in electricity is achieved,the“pseudo net zero emissions”effect of the transportation sector will inevitably be accompanied by a quiet shifting of carbon responsibility.1 This shift is undoubtedly fatal for both net zero emissions at the national level and carbon responsibility at the industry level;however,the corresponding effects have not yet been clarified.

关键词： neutral doubt shifting

Hydro-mechanical-electrical simulations of synthetic faults in two orthogonal directions with shear-induced anisotropy

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第11期16卷 4428-4439页

作者： Kazuki Sawayama Takuya Ishibashi Fei Jiang Takeshi Tsuji Institute for Geothermal Sciences Kyoto UniversityBeppuJapan Fukushima renewable energy Institute AISTKoriyamaJapan department of Engineering Yamaguchi UniversityUbeJapan School of Engineering University of TokyoTokyoJapan

Fluid flow in fractures controls subsurface heat and mass transport,which is essential for developing enhanced geothermal systems and radioactive waste *** permeability is controlled by fracture microstructure(***,roughness,and tortuosity),but in situ values and their anisotropy have not yet been *** advances in geophysical techniques allow the detection of changes in electrical conductivity due to changes in crustal stress and these techniques can be used to predict subsurface fluid ***,the paucity of data on fractured rocks hinders the quantitative interpretation of geophysical monitoring data in the ***,considering different shear displacements and chemical erosions,an investigation was conducted into the hydraulic-electric relationship as an elevated stress change in *** simulation of fracture flows was achieved using the lattice Boltzmann method,while the electrical properties were calculated through the finite element method,based on synthetic faults incorporating elastic-plastic *** results show that the hydraulic and electrical properties depend on the rock's geometric properties(*** length,roughness,and shear displacement).The permeability anisotropy in the direction parallel or perpendicular to the shear displacement is also notable in high stress ***,the permeability econductivity(i.e.,formation factor)relationship is unique under all conditions and follows a linear trend in logarithmic ***,both matrix porosity and fracture spacing alter this *** increase the slope of the linear trend,thereby changing the sensitivity of electrical observations to permeability changes.

关键词： Fracture flow Permeability electrical conductivity Lattice Boltzmann method Anisotropy Chemical erosion Enhanced geothermal system

熔融和辐射对垂直多孔嵌入微通道MHD混合对流换热的影响

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Journal of Central South University 2023年第11期30卷 3670-3681页

作者： A T AKINSHILO A O ILEGBUSI H M ALI M SANUSI M G SOBAMOWO department of Mechanical Engineering University of LagosAkoka-YabaLagosNigeria department of Mechanical Engineering Yaba College of TechnologyLagosNigeria Mechanical Engineering department King Fahd University of Petroleum and MineralsDharan 31261Saudi Arabia Interdisciplinary Research Center of renewable energy and Power systems(IRC-REPS) King Fahd University of Petroleum and MineralsDharan 31261Saudi Arabia department of Mechanical Engineering Obafemi Awolowo UniversityIle-IfeOsunNigeria

研究了导电和非导电两种壁型多孔微通道的熔融和滑移效应对混合对流换热的影响。采用高阶常微分非线性耦合模型,研究了横向磁场作用下流体在微通道内注入和喷出的流动力学。这些都是在通过相似变换完成的。采用解析解的同伦摄动方法对... 详细信息

研究了导电和非导电两种壁型多孔微通道的熔融和滑移效应对混合对流换热的影响。采用高阶常微分非线性耦合模型,研究了横向磁场作用下流体在微通道内注入和喷出的流动力学。这些都是在通过相似变换完成的。采用解析解的同伦摄动方法对控制热流体输运的力学模型进行了分析,并利用已有文献在简单条件下进行了验证并得到满意的结果。研究了流体输送过程中传热流变参数的影响,以提高系统运行效率,降低能耗,从而最大限度地降低成本。结果表明,熔体和辐射对热边界层的共同作用使热边界层的厚度逐渐减小。当辐射参数(R)在1

关键词：强化传热熔融微通道辐射优化多孔介质

Electric Generators and Motors: an overview

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CES Transactions on electrical Machines and systems 2017年第1期1卷 3-14页

作者： Ion Boldea department of electrical Engineering Romanian Academy and University Politehnica TimișoaraRomania

Starting with Faraday’s law of electromagnetic induction in 1831,electric(electromagnetic)machines have been developed ever since as“assembles”of electric and magnetic coupled circuits that convert mechanical to electrical energy(in generators)and vice versa(in motors),via magnetic energy *** and motors are *** Maxwell four equations(laws)later in 19th Century have prompted the rapid development of all basic(*** and travelling field AC machines by *** by 1930 AC(alternating current)power(energy)systems evolved by connecting in parallel electric synchronous generators(with voltage boost and buck electric transformers for efficient AC power transmission lines)of rather constant frequency and voltage,driven by turbines(prime movers)that harness fossil(coal,gas or nuclear fuels),thermal or hydro *** last 50 years have witnessed a dramatic extension of generators power/unit,renewable energy generators and of variable speed AC motor drives in applications with variable output such as ventilators,pumps compressors,conveyors,orr-mills,electric transport(mobility),industrial automation,robotics,home appliances and *** formidable development,required by the need of more but cleaner energy,was mainly driven by power electronics,better materials,better modeling,design methodologies and digital *** humble inaugural overview attempts to combine a brief history of electrical generators and motors with recent progress and trends in their design and control,for representative applications.

关键词： Electric generator linear electric machines induction synchronous machines.

Recent advances in heterogeneous catalysis of solar-driven carbon dioxide conversion

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Journal of Environmental Sciences 2024年第6期140卷 165-182页

作者： Jun Xu Farzaneh Arabpour Roghabadi Ying Luo Vahid Ahmadi Qian Wang Zheng Wang Hong He State Key Joint Laboratory of Environment Simulation and Pollution Control Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China College of Chemistry and Chemical Engineering Henan Polytechnic UniversityJiaozuoHenan 454000China department of Process Engineering Faculty of Chemical EngineeringTarbiat Modares UniversityTehranIran Optoelectronics and Nanophotonics Research Group Faculty of Electrical and Computer EngineeringTarbiat Modares UniversityTehranIran Graduate School of Engineering Nagoya UniversityFuro-choChikusa-kuNagoya 464-8603Japan

Solar-driven carbon dioxide(CO_(2))conversion including photocatalytic(PC),photoelectrochemical(PEC),photovoltaic plus electrochemical(PV/EC)systems,offers a renewable and scalable way to produce fuels and high-value chemicals for environment and energy *** review summarizes the basic fundament and the recent advances in the field of solar-driven CO_(2)*** the visible-light absorption is an important strategy to improve solar energy conversion *** separation and migration of photogenerated charges carriers to surface sites and the surface catalytic processes also determine the photocatalytic *** engineering including co-catalyst loading,defect engineering,morphology control,surface modification,surface phase junction,and Z-scheme photocatalytic system construction,have become fundamental strategies to obtain high-efficiency *** to photocatalysis,these strategies have been applied to improve the conversion efficiency and Faradaic efficiency of typical PEC *** PV/EC systems,the electrode surface structure and morphology,electrolyte effects,and mass transport conditions affect the activity and selectivity of electrochemical CO_(2)***,the challenges and prospects are addressed for the development of solar-driven CO_(2)conversion system with high energy conversion efficiency,high product selectivity and stability.

关键词： Solar-driven CO_(2)reduction Photocatalytic system Photoelectrochemical system Photovoltaic plus electrochemical system Surface/interface engineering

Dielectric behaviours of bio-derived epoxy resins from cashew nutshell liquid

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High Voltage 2021年第2期6卷 255-263页

作者： Mulan Mu Alun Vaughan department of Electronics and Computer Science Tony Davies High Voltage LaboratoryUniversity of SouthamptonSouthamptonUK Novel Polymer Technology Section TWI LtdCambridgeUK

In this study,four commercially available bio-derived epoxy systems(extracted from cashew nutshell liquid)were prepared and *** glass transition temperature(Tg),dielectric spectroscopy,DC conductivity and breakdown properties of these epoxy resins were *** scanning calorimetry(DSC)demonstrated that the T_(g) of the investigated systems ranged from 67 to 122°*** DC conductivity was very low(systems showed a strong temperature dependence of the electrical conductivity and exhibited sharp increase around their respective T_(g).Arrhenius analysis led to activation energy,E_(a),values around 1 eV;higher E_(a) values were observed in systems with a lower T_(g).Dielectric spectroscopy revealed a flat and low response at temperature below T_(g).However,both the real and imaginary permittivity increased with decreasing frequency at mid to low frequencies as the temperatures approached T_(g).The variations of AC breakdown strength of all samples were not statistically significant,but the DC breakdown strength of sample 2503Aþ2002B was higher than the others,which might be due to reduced charge transport in this *** results indicate that novel bio-derived epoxy systems from renewable sources are potential alternatives for traditional petroleum-based epoxy systems in certain insulation applications.

关键词： conductivity resins liquid