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Research on Total Electric Field Prediction Method of Ultra-High Voltage Direct Current Transmission Line Based on Stacking Algorithm
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作者 Yinkong Wei Mucong Wu +3 位作者 Wei Wei Paulo R.F.Rocha Ziyi Cheng Weifang Yao 《Computer Systems Science & Engineering》 2024年第3期723-738,共16页
Ultra-high voltage(UHV)transmission lines are an important part of China’s power grid and are often surrounded by a complex electromagnetic environment.The ground total electric field is considered a main electromagn... Ultra-high voltage(UHV)transmission lines are an important part of China’s power grid and are often surrounded by a complex electromagnetic environment.The ground total electric field is considered a main electromagnetic environment indicator of UHV transmission lines and is currently employed for reliable long-term operation of the power grid.Yet,the accurate prediction of the ground total electric field remains a technical challenge.In this work,we collected the total electric field data from the Ningdong-Zhejiang±800 kV UHVDC transmission project,as of the Ling Shao line,and perform an outlier analysis of the total electric field data.We show that the Local Outlier Factor(LOF)elimination algorithm has a small average difference and overcomes the performance of Density-Based Spatial Clustering of Applications with Noise(DBSCAN)and Isolated Forest elimination algorithms.Moreover,the Stacking algorithm has been found to have superior prediction accuracy than a variety of similar prediction algorithms,including the traditional finite element.The low prediction error of the Stacking algorithm highlights the superior ability to accurately forecast the ground total electric field of UHVDC transmission lines. 展开更多
关键词 DC transmission line total electric field effective data multivariable outliers LOF algorithm Stacking algorithm
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Magnetic Field Curves and Magnetic Equipotential Surfaces around Crossing Electrical Wires Replacing Classical Magnetic Field Lines
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作者 Geoffroy Auvert 《Open Journal of Applied Sciences》 2024年第8期1996-2008,共13页
This article is based on a recent model specifically defining magnetic field values around electrical wires. With this model, calculations of field around parallel wires were obtained. Now, this model is extended with... This article is based on a recent model specifically defining magnetic field values around electrical wires. With this model, calculations of field around parallel wires were obtained. Now, this model is extended with the new concept of magnetic equipotential surface to magnetic field curves around crossing wires. Cases of single, double, and triple wires are described. Subsequent article will be conducted for more general scenarios where wires are neither infinite nor parallel. 展开更多
关键词 Magnetic field Value Magnetic field Vector Magnetic field line Magnetic field Curve Equipotential Surface Crossing Electrical Wires Magnetic Cross Product
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Simultaneous resonance of an axially moving ferromagnetic thin plate under a line load in a time-varying magnetic field 被引量:1
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作者 Xie Mengxue Hu Yuda Xu Haoran 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2023年第4期951-963,共13页
In this paper,the simultaneous resonance of a ferromagnetic thin plate in a time-varying magnetic field,having axial speed and being subjected to a periodic line load,is studied.Based on the large deflection theory of... In this paper,the simultaneous resonance of a ferromagnetic thin plate in a time-varying magnetic field,having axial speed and being subjected to a periodic line load,is studied.Based on the large deflection theory of thin plates and electromagnetic field theory,the nonlinear vibration differential equation of the plate is obtained by using the Hamilton′s principle and the Galerkin method.Then the boundary condition in which the longer opposite sides are clamped and hinged is considered.The dimensionless nonlinear differential equations are solved by using the method of multiple scales,and the analytical solution is given.In addition,the stability analysis is also carried out by using Lyapunov stability theory.Through numerical analysis,the variation curves of system resonance amplitude with frequency tuning parameter,magnetic field strength and external excitation amplitude are obtained.Different parameters that have significant effects on the response of the system,such as the thickness,the axial velocity,the magnetic field intensity,the position,and the frequency of external excitation,are considered and analyzed.The results show that the system has multiple solution regions and obvious nonlinear coupled characteristics. 展开更多
关键词 ferromagnetic thin plate time-varying magnetic field simultaneous resonance axially moving line load
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Rolling Force and Rolling Moment in Spline Cold Rolling Using Slip-line Field Method 被引量:9
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作者 ZHANG Dawei LI Yongtang +1 位作者 FU Jianhua ZHENG Quangang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2009年第5期688-695,共8页
Rolling force and rolling moment are prime process parameter of external spline cold rolling. However, the precise theoretical formulae of rolling force and rolling moment are still very fewer, and the determination o... Rolling force and rolling moment are prime process parameter of external spline cold rolling. However, the precise theoretical formulae of rolling force and rolling moment are still very fewer, and the determination of them depends on experience. In the present study, the mathematical models of rolling force and rolling moment are established based on stress field theory of slip-line. And the isotropic hardening is used to improve the yield criterion. Based on MATLAB program language environment, calculation program is developed according to mathematical models established. The rolling force and rolling moment could be predicted quickly via the calculation program, and then the reliability of the models is validated by FEM. Within the range of module of spline m=0.5-1.5 mm, pressure angle of reference circle α=30.0°-45.0°, and number of spline teeth Z=19-54, the rolling force and rolling moment in rolling process (finishing rolling is excluded) are researched by means of virtualizing orthogonal experiment design. The results of the present study indicate that: the influences of module and number of spline teeth on the maximum rolling force and rolling moment in the process are remarkable; in the case of pressure angle of reference circle is little, module of spline is great, and number of spline teeth is little, the peak value of rolling force in rolling process may appear in the midst of the process; the peak value of rolling moment in rolling process appears in the midst of the process, and then oscillator weaken to a stable value. The results of the present study may provide guidelines for the determination of power of the motor and the design of hydraulic system of special machine, and provide basis for the farther researches on the precise forming process of external spline cold rolling. 展开更多
关键词 external spline cold rolling slip-line field method rolling force rolling moment
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Temperature Field in Laser Line Scanning Thermography: Analytical Calculation and Experiment
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作者 Yin Li Yuanjia Song +2 位作者 Zhengwei Yang Haijun Jiang Bowen Liu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第10期1001-1018,共18页
The temperature field in laser line scanning thermography is investigated comprehensively in this work,including analytical calculation and experiment.Firstly,the principle of laser line scanning thermography is analy... The temperature field in laser line scanning thermography is investigated comprehensively in this work,including analytical calculation and experiment.Firstly,the principle of laser line scanning thermography is analyzed.On this basis,a physical laser line scanning model is proposed.Afterwards,based on Fourier transform(FT)and segregation variablemethod(SVM),the heat conduction differential equation in laser line scanning thermography is derived in detail.The temperature field of the composite-based coatings model with defects is simulated numerically.The results show that the laser line scanning thermography can effectively detect the defects in the model.The correctness of the analytical calculation is verified by comparing the surface temperature distribution obtained by analytical calculation and numerical simulation.Additionally,an experiment is carried out and the changeable surface temperature obtained by analytical calculation is compared with the experimental results.It shows that the error of maximum temperature obtained by analytical calculation and by experiment is 8%with high accuracy,which proves the correctness of analytical calculation and enriches the theoretical foundation of laser line scanning thermography. 展开更多
关键词 Temperature field laser line scanning thermography analytical calculation numerical simulation EXPERIMENT
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Slip-line field solution for ultimate bearing capacity of a pipeline on clayey soils 被引量:2
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作者 Fuping Gao Bo Zhao 《Theoretical & Applied Mechanics Letters》 2012年第5期14-17,共4页
A slip-line field solution is presented for the ultimate bearing capacity of the pipeline on a purely-cohesive clay soil, taking into account the circular configuration of the pipe, the pipe embedment, and the pipe-so... A slip-line field solution is presented for the ultimate bearing capacity of the pipeline on a purely-cohesive clay soil, taking into account the circular configuration of the pipe, the pipe embedment, and the pipe-soil interfacial cohesion. The derived bearing capacity factors for a smooth rigid pipe limit to those for the conventional rectangular strip footing while the pipe embedment approaches zero. Parametric studies indicate that, the pipe-soil interfacial properties have much influence on the bearing capacity for the pipe foundation on clayedy soils. 展开更多
关键词 collapse loads slip-line field theory submarine pipeline shallow foundation clayedy soils
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Analysis and Simulation of the Influence of Electromagnetic Fields on Living Beings near HV Power Lines Using the FDTD Method
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作者 Anthony Bassesuka Sandoka Nzao 《Open Journal of Applied Sciences》 2023年第12期2343-2359,共17页
Recent decades have seen rapid advances in the field of electrical engineering, such that our environment has become a sea of electrical and magnetic signals, raising questions about the possible effects of low-freque... Recent decades have seen rapid advances in the field of electrical engineering, such that our environment has become a sea of electrical and magnetic signals, raising questions about the possible effects of low-frequency electromagnetic fields on the environment and which are capable of modifying and destroying our ecosystem. Particular interest was given in this article due to a massive influx of population living near high voltage lines. The analysis and simulation of the influence of low frequency electromagnetic fields on living beings in the vicinity of high voltage sources 132 kV and 220 kV in urban areas in DR Congo is the subject of our research with a view to estimating the level of exposure of humans to low frequency electromagnetic fields. To carry out our research, we used the classic method of analyzing the field produced near a high voltage line based on Maxwell’s image theory, the Maxwell-Gauss theorem and Maxwell-Ampère theorem to model and quantify low-frequency electromagnetic fields in the vicinity of high-voltage lines. The 2D FDTD numerical formulation was developed from telegraphers’ equations and allowed us to obtain models of current and voltage induced by electromagnetic fields on living beings below and near HV lines. The different simulations carried out on the proposed models illustrate the effects of the electrical and geometric parameters of the pylons on the distribution of the electromagnetic field in the vicinity of the HV lines. The results obtained were compared to the safety limits recommended by the standards. 展开更多
关键词 Low Frequency Electromagnetic field Modeling field and Health Maxwell’s Equations FDTD Method Electromagnetic Compatibility High Voltage line
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Slip-Line Field Theory of Transversely Isotropic Body
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作者 阮怀宁 王维襄 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1994年第4期335-345,共11页
A slip-line field theory of transversely isotropic body is proposed in the presentpaper in order to deal with problems in geology and geotechniques.The Goldenblat-Kopnov failure criterion is employed.The parameters in... A slip-line field theory of transversely isotropic body is proposed in the presentpaper in order to deal with problems in geology and geotechniques.The Goldenblat-Kopnov failure criterion is employed.The parameters in it are treated as functions of tempperature It is applicable to transverse isotropic media in non-uniform temperaturefield.The basic equtions of plastic deformation are developed while the associated ru-les of flow are derived.By means of characteristic line theory,slip-line slope formulasand laws of variation of stress and velocity along slip lines are obtained,The indenta-tion on semi-infinite media is calculated.The theory developed in this paper may be simplified into many classical theories such as Mises,Hill,and Coulomb ones,This complicated theory may be applied to geotechniques,geological structures,petroleumindustry,mining engineering,etc. 展开更多
关键词 slip-line field. transversely isotropic. non-uniform temperaturefield. failure criterion. limit equilibrium
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Modeling Density and Anisotropy of Energetic Electrons Along Magnetic Field Lines 被引量:3
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作者 肖伏良 冯学尚 《Plasma Science and Technology》 SCIE EI CAS CSCD 2006年第3期279-284,共6页
The electromagnetic wave growth or damping depends basically on the number density and anisotropy of energetic particles as the resonant interaction takes place between the particles and waves in the magnetosphere. Th... The electromagnetic wave growth or damping depends basically on the number density and anisotropy of energetic particles as the resonant interaction takes place between the particles and waves in the magnetosphere. The variance of both the number density and anisotropy along the magnetic field line is evaluated systematically by modeling four typically prescribed distribution functions. It is shown that in the case of "the positive anisotropy" (namely, the perpendicular temperature T⊥ exceeds the parallel temperature T||), the number density of energetic electrons always decreases with the magnetic latitude for a regular increasing magnetic field and the maximum wave growth is therefore generally confined to the equator where the resonant energy is minimum, and the number density is the largest. However, the "loss-cone" anisotropy of the electrons with a "pancake" distribution or kappa distribution keeps invariant or nearly invariant, whereas the "temperature" anisotropy with a pure bi-Maxwellian distribution or Ashour-Abdalla and Kennel's distributions decreases with the magnetic latitude. The results may provide a useful approach to evaluating the number density and anisotropy of the energetic electrons at latitudes where the observation information is not available. 展开更多
关键词 number density ANISOTROPY distribution function magnetic field line
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EXACT SOLUTIONS OF NEAR CRACK LINE FIELDS FOR MODE I CRACK UNDER PLANE STRESS CONDITION IN AN ELASTIC-PERFECTLY PLASTIC SOLID 被引量:1
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作者 易志坚 王士杰 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1996年第4期351-358,共8页
The near crack line analysis method has been used in the present paper,The classical small scale yielding conditions have been completely abandoned in the analyses and one inappropriate matching condition used to be u... The near crack line analysis method has been used in the present paper,The classical small scale yielding conditions have been completely abandoned in the analyses and one inappropriate matching condition used to be used at the elasticplastic boundary has been corrected.The reasonable solution of the plastic stresses near the crack line region has been established.By matching the plastic stresses with the exact elastic stresses at the elastic-plastic boundary,the plastic stresses the length of the plastic zone and the unit normal vector of the elastic-plastic boundary near the crock line region have been obtained for a mode I crack under uniaxial tension,as well as a mode I crack under biaxial tension,which shows that for both conditions the plastic stress componentsσy, and σsy.he length of the plastic zone and the unit normal vector of the elastic-plastic boundary are quite the same while the plastic stress σs is different. 展开更多
关键词 mode I plane stress crack crack line field plastic zone elastic zone
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Higher-Order Line Element Analysis of Potential Field with Slender Heterogeneities 被引量:2
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作者 H.-S.Wang H.Jiang B.Yang 《Computers, Materials & Continua》 SCIE EI 2016年第3期145-161,共17页
Potential field due to line sources residing on slender heterogeneities is involved in various areas,such as heat conduction,potential flow,and electrostatics.Often dipolar line sources are either prescribed or induce... Potential field due to line sources residing on slender heterogeneities is involved in various areas,such as heat conduction,potential flow,and electrostatics.Often dipolar line sources are either prescribed or induced due to close interaction with other objects.Its calculation requires a higher-order scheme to take into account the dipolar effect as well as net source effect.In the present work,we apply such a higher-order line element method to analyze the potential field with cylindrical slender heterogeneities.In a benchmark example of two parallel rods,we compare the line element solution with the boundary element solution to show the accuracy as a function in terms of rods distance.Furthermore,we use more complicated examples to demonstrate the capability of the line element technique. 展开更多
关键词 ELECTROSTATICS Heat conduction Integral equation technique line element method Mesh reduction method Potential field problems
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The study of slip line field and upper bound method based on associated flow and non-associated flow rules 被引量:2
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作者 Zheng Yingren Deng Chujian Wang Jinglin 《Engineering Sciences》 EI 2010年第3期21-40,共20页
At present, associated flow rule of traditional plastic theory is adopted in the slip line field theory and upper bound method of geotechnical materials. So the stress characteristic line conforms to the velocity line... At present, associated flow rule of traditional plastic theory is adopted in the slip line field theory and upper bound method of geotechnical materials. So the stress characteristic line conforms to the velocity line. It is proved that geotechnical materials do not abide by the associated flow rule. It is impossible for the stress characteristic line to conform to the velocity line. Generalized plastic mechanics theoretically proved that plastic potential surface intersects the Mohr-Coulomb yield surface with an angle, so that the velocity line must be studied by non-associated flow rule. According to limit analysis theory, the theory of slip line field is put forward in this paper, and then the ultimate beating capacity of strip footing is obtained based on the associated flow rule and the non-associated flow nile individually. These two results are identical since the ultimate bearing capacity is independent of flow role. On the contrary, the velocity fields of associated and non-associated flow rules are different which shows the velocity field based on the associat- ed flow rule is incorrect. 展开更多
关键词 slip line field upper bound method associated flow rule non-associated flow rule generalized plastic theory
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Study on the Environmental Impact of Oil and Gas Field Development on the Ecological Red Line Area 被引量:1
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作者 Yunshi XIONG Zhihong GUO +1 位作者 Tao LIANG Qichen GAO 《Meteorological and Environmental Research》 CAS 2020年第3期70-73,80,共5页
To cooperate with the five ministries and commissions of the state to carry out joint investigation on the environmentally sensitive areas involved in oil and gas exploration and development,for the problems found in ... To cooperate with the five ministries and commissions of the state to carry out joint investigation on the environmentally sensitive areas involved in oil and gas exploration and development,for the problems found in survey,containing complex type and numerous amount of ecologically sensitive space and ecological red line involved in oil and gas field enterprises,scientific nature of delimitation,lack of strong support of laws and regulations for forced withdrawal of oil and gas production facilities in these areas,some countermeasures and suggestions were proposed,such as further evaluating and combing scope and functional zoning of existing environmentally sensitive areas and ecological red lines,treating differently,enhancing pertinence of prohibition in ecologically sensitive regions,declining blindness of the withdrawal of oil and gas facilities in environmentally sensitive areas,strengthening seriousness of approval of exploration and mining rights of oil and gas resources,and establishing strategic reserve exploration and hierarchical development mechanism. Moreover,oil and gas field enterprises should integrate more efforts to ① accelerate to find out the current situation of environmental quality,② adhere to developing in protection,and protecting in development,③ increase attention and participation strengthen of providing technical support for national oil and gas exploration and development strategy evaluation,④ accelerate communication and docking with local governments on the ecological red line,⑤ actively strive to be included in the positive list management of local governments,⑥ accelerate to establish and perfect primary database of oil and gas production and facilities construction,and ⑦ document management information system of the ecological red line. 展开更多
关键词 Oil and gas fields Exploration and development Ecological red line Environmentally sensitive area Environmental effect
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THE PROBLEM OF PARAMETRIC INTEGRATION TO THE SLIP LINE FIELD IN THE COMPRESSION OF THICK WORKPIECE
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作者 赵德文 张卫军 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1993年第10期963-969,共7页
An integration depending on a parameter to the compression of a thick workpiece has been obtained. For the conventional prevailing numerical formulaa definite functional relationship bet-ween and y is found. Therefore... An integration depending on a parameter to the compression of a thick workpiece has been obtained. For the conventional prevailing numerical formulaa definite functional relationship bet-ween and y is found. Therefore a parametric integration can be used to get an analytical solution. Take the slip line field for l/h= 0.121 as an example, the analytical solution is basically the same as the prevailing numerical one. It is justified theoretically that for the slip line field a parametric integration is perfectly possible for a satisfactory analytical solution. 展开更多
关键词 thick workpiece slip line field parametric integration analytical solution
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Method of lines for temperature field of functionally graded materials
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作者 戴耀 孙琦 +2 位作者 郝贵祥 燕秀发 李永东 《Journal of Central South University》 SCIE EI CAS 2005年第S2期230-232,共3页
The finite element method (FEM) and the boundary element method (BEM) are often adopted. However, they are not convenient to spatially vary thermal properties of functionally graded material (FGM). Therefore, the meth... The finite element method (FEM) and the boundary element method (BEM) are often adopted. However, they are not convenient to spatially vary thermal properties of functionally graded material (FGM). Therefore, the method of lines (MOL) is introduced to solve the temperature field of FGM. The basic idea of the method is to semi-discretize the governing equation into a system of ordinary differential equations (ODEs) defined on discrete lines by means of the finite difference method. The temperature field of FGM can be obtained by solving the ODEs. The functions of thermal properties are directly embodied in these equations and these properties are not discretized in the domain. Thus, difficulty of FEM and BEM is overcome by the method. As a numerical example, the temperature field of a plane problem is analyzed for FGMs through varying thermal conductivity coefficient by the MOL. 展开更多
关键词 functionally GRADED MATERIALS METHOD of lineS TEMPERATURE field
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Correction of Observation Interference on Z component of Geomagnetic Field From DC Power Lines 被引量:8
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作者 TANG Bo ZHANG Jiangong +2 位作者 MENG Suimin LIU Xingfa DENG Changzheng 《中国电机工程学报》 EI CSCD 北大核心 2012年第30期I0021-I0021,23,共1页
为减小直流输电线路对地磁场观测的干扰,采用数学计算的方法精确求解了线路对地磁Z分量的干扰水平。以观测点为原点建立了地磁仪器观测点坐标系,推导了观测点坐标系各坐标轴在地心坐标系中的单位矢量表达式。根据空间矢量点积的定义,得... 为减小直流输电线路对地磁场观测的干扰,采用数学计算的方法精确求解了线路对地磁Z分量的干扰水平。以观测点为原点建立了地磁仪器观测点坐标系,推导了观测点坐标系各坐标轴在地心坐标系中的单位矢量表达式。根据空间矢量点积的定义,得到了空间电流磁场矢量投影到地磁Z分量方向的求解公式。利用推导的公式和直流线路电流磁场三维计算模型,最终求得直流线路对地磁Z分量观测的干扰水平。由此,开发了"直流线路对地磁观测干扰校正系统",并开展了地磁台站和野外联合地磁观测干扰实验。结果表明,直流线路和地磁观测台站距离不超过10km时,提出的数学模型和计算方法误差不超过5%。 展开更多
关键词 干扰修正 电源线 地磁场 观测站 高压直流输电工程 DC Z分量 地震台站
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Research on Total Electric Field for DC Lines Converted from Double-Circuit AC Lines
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作者 Xiaoqian Ma Jiayu Lu +1 位作者 Kun He Wensheng Gao 《Energy and Power Engineering》 2017年第4期598-610,共13页
With rapid growth of power demand, transmission capacity is also in urgent need of upgrading. In some cases, converting existing AC transmission lines to DC lines can Improve the transmission capacity and reduce the c... With rapid growth of power demand, transmission capacity is also in urgent need of upgrading. In some cases, converting existing AC transmission lines to DC lines can Improve the transmission capacity and reduce the construction investment. In this paper, the upstream finite element method was expanded to calculate the total electric field of same tower multi-circuit DC lines converted from double-circuit AC lines, and the validity of the algorithm was confirmed by experiments. Taking a DC line converted from a typical same tower 500 kV double-circuit AC transmission line as an example, the surface electric field and the ground total electric field in different pole conductor arrangement schemes were calculated and analyzed, and the critical height of pole conductors for DC lines in residential and non-residential area were determined. Then, the corridor width of DC and AC lines at critical height in residential and non-residential areas before and after AC-DC line transformation were compared. The results indicate that for DC lines converted from common 500 kV double-circuit AC lines, the ground total electric field can meet the requirements of corresponding standard with appropriate pole conductor arrangement schemes. 展开更多
关键词 DC lineS Converted from AC lineS Multi-Circuit DC line at SAME Tower Pole Conductor BUNDLES Arrangement Scheme Total Electric field line-to-Ground Distance Corridor Width
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Slip Line Field Solution for Second Pass in Lubricated 4-High Reversing Cold Rolling Sheet Mill
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作者 Oluleke O. Oluwole Olayinka Olaogun 《Engineering(科研)》 2011年第12期1225-1233,共9页
The development of a possible slip line field (slf) for theoretical calculations of the deforming pressure (load) in a second pass of a lubricated cold rolling sheet mill and validation using values from an aluminium ... The development of a possible slip line field (slf) for theoretical calculations of the deforming pressure (load) in a second pass of a lubricated cold rolling sheet mill and validation using values from an aluminium sheet rolling mill was done in this work. This will be relevant in the manufacturing industries providing an easy method for determining necessary applied rolling load. Experimental rolling was carried out to observe the shear lines in the deformation field. Construction of possible slip line field model was developed adhering strictly to assumptions of rigid plastic model. Calculation of the deforming force/load was achieved using Hencky’s equation. Results showed that the load calculations for constructed slip line field using aluminium sheet rolling as an example tallied with values obtained from Tower Aluminium rolling mill. Slip line fields constructed for the second pass described adequately the rolling pressure in the cold rolling process, giving a valid solution of the exact load estimates on comparison with the industrial load values. Roll pressure along the arc of contact rose fairly linearly from the entrance to a maximum at the exit point. This work showed that slf for the first pass in a cold rolling mill cannot be used for subsequent passes;it requires construction of slfs for each pass in the cold rolling process. 展开更多
关键词 SLIP line field(Slf) STRIP Cold ROLLING Rigid Plastic Model Hencky’s Equation
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Three-dimensional Model Analysis of Electric Field Excited by Multi-circuit Intersecting Overhead Transmission Lines 被引量:2
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作者 XIAO Dongping LEI Hui ZHANG Zhanlong HE Wei 《高电压技术》 EI CAS CSCD 北大核心 2013年第8期2006-2013,共8页
This work is carried out to predict the special distribution of electric field induced by multi-circuit intersecting overhead high-voltage (HV) transmission lines (TLs) within a large range without any expensive and t... This work is carried out to predict the special distribution of electric field induced by multi-circuit intersecting overhead high-voltage (HV) transmission lines (TLs) within a large range without any expensive and time-consuming computation. The two main parts of the presented methodology are 1) setting up a three-dimensional (3D) model to calculate the electric field based on combining ca- tenary equations with charge simulation method and 2) calculating the hybrid electric field excited by multi-circuit intersecting TLs using coordinate transformation and superposition technique. Examples of different TLs configurations, including a 220 kV single-circuit hori- zontally configured TLs, a 500 kV single-circuit triangularly configured TLs and a combination of the 220 kV TLs and the 550 kV TLs, are illustrated to verify the validity of this methodology. A more complicatal configurations, including a 500 kV double-circuit TLs and two 220 kV single-circuit horizontally configured TLs, are also calculated. Conclusions were drawn from the simulation: 1) The presented 3D model outperforms 2D models in describing the electric field distribution generated by practical HV TLs with sag and span. 2) Coordinate trans- formation and superposition technique considerably simplify the electric field computation for multi-circuit TLs configurations, which makes it possible to deal with complex engineering problems. 3) The electric field in the area covered by multiple intersecting overhead TLs is distorted and the hybrid electric field strength in some partial region increases so sharply that it might exceed the admissible value. 4) The configuration parameters of the TLs and the spatial configuration of multi-circuit TLs, for instance, the height of TLs, the length of span and the intersection angle of multiple circuits, influence the strength and the distribution of hybrid electric field. The influence regularities sum- marized in this paper can be referred by future TL designs to meet the electromagnetic environmental protection regulations. 展开更多
关键词 架空输电线路 电场分布 模型分析 相交 三维 多路 激发 220千伏
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Correlations of the Evolution of a CCOPE Squall Line with Surface Thermodynamics and Kinematic Fields
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作者 徐玉貌 J.C.Fankhauser 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1989年第1期99-112,共14页
A midlatitude squall line passed over the array of the Cooperative Convective Precipitation Experiment (CCOPE) on 1 August 1981. The structure and evolution of the squall line, and the correlations of the storm with s... A midlatitude squall line passed over the array of the Cooperative Convective Precipitation Experiment (CCOPE) on 1 August 1981. The structure and evolution of the squall line, and the correlations of the storm with surface thermodynamics and kinematic fields are investigated, mainly by using radar and surface mesonet data in CCOPE. The storm-wide precipitation efficiency is also estimated.The squall line was of an obvious process of metabolism. Thirty-four cells formed successively in front of the primary storm and eventually merged into it during the period 1700-2010 MDT. The newest cells formed near surface equivalent potential temperature maxima, and near surface moisture flux convergence zones or / and the 'temperature break lines'. The thunderstorm rainfall, with the precipitation efficiency of 54%, lags 25-30 min behind the moisture flux convergence on the average. 展开更多
关键词 MDT Correlations of the Evolution of a CCOPE Squall line with Surface Thermodynamics and Kinematic fields
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