A Study on a Conductor System for Investigation of Proximity Effect

The proximity effect is very significant to investigate transient peak voltages and EMC related problems of a conductor system. In this paper, effect of energized single conductor in close proximity of an Al plate when an Al plate is used as return path is investigated to find out proximity effect. The analysis involves simulation by the Finite Time Domain Method (FDTD) in comparison with field measurements. It is observed that the current distribution is uneven in pipe conductor due to the proximity effect of varying heights from ground.

A Solvent-Free Covalent Organic Framework Single-Ion Conductor Based on Ion-Dipole Interaction for All-Solid-State Lithium Organic Batteries

Single-ion conductors based on covalent organic frameworks(COFs)have garnered attention as a potential alternative to currently prevalent inorganic ion conductors owing to their structural uniqueness and chemical versatility.However,the sluggish Li+conduction has hindered their practical applications.Here,we present a class of solvent-free COF single-ion conductors(Li-COF@P)based on weak ion-dipole interaction as opposed to traditional strong ion-ion interaction.The ion(Li+from the COF)-dipole(oxygen from poly(ethylene glycol)diacrylate embedded in the COF pores)interaction in the Li-COF@P promotes ion dissociation and Li+migration via directional ionic channels.Driven by this single-ion transport behavior,the Li-COF@P enables reversible Li plating/stripping on Li-metal electrodes and stable cycling performance(88.3%after 2000 cycles)in organic batteries(Li metal anode||5,5’-dimethyl-2,2’-bis-p-benzoquinone(Me2BBQ)cathode)under ambient operating conditions,highlighting the electrochemical viability of the Li-COF@P for all-solid-state organic batteries.

Critical current degradation in an epoxy-impregnated rare-earth Ba_(2)Cu_(3)O_(7-x)coated conductor caused by damage during a quench

High-temperature superconducting(HTS)rare-earth Ba_(2)Cu_(3)O_(7-x)(REBCO)coated conductors(CCs)have significant potential in high-current and high-field applications.However,owing to the weak interface strength of the laminated composite REBCO CCs,the damage induced by the thermal mismatch stress under a combination of epoxy impregnation,cooling,and quenching can cause premature degradation of the critical current.In this study,a three-dimensional(3D)electromagnetic-thermal-mechanical model based on the H-formulation and cohesive zone model(CZM)is developed to study the critical current degradation characteristics in an epoxy-impregnated REBCO CC caused by the damage during a quench.The temperature variation,critical current degradation of the REBCO CC,and its degradation onset temperature calculated by the numerical model are in agreement with the experimental data taken from the literature.The delamination of the REBCO CC predicted by the numerical model is consistent with the experimental result.The numerical results also indicate that the shear stress is the main contributor to the damage propagation inside the REBCO CC.The premature degradation of the critical current during a quench is closely related to the interface shear strength inside the REBCO CC.Finally,the effects of the coefficient of thermal expansion(CTE)of the epoxy resin,thickness of the substrate,and substrate material on the critical current degradation characteristics of the epoxy-impregnated REBCO CC during a quench are also discussed.These results help us understand the relationship between the current-carrying degradation and damage in the HTS applications.

Synthesis and Characterization of Y^3＋, W^6＋-Doped Mineral Lithium Fast Ion Conductor Li1.2＋x-y YxTi1.9-xAl0.1Si0. 1Wy P2.9-yO12 System

New lithium fast ion conductors of Li1.2 ＋ x - y Yx Ti1.9 - x Al0.1Si0. 1Wy P2.9 - y O12 based on LiTi2（PO4）3 were prepared by high temperature solid state reaction using refined natural kaolinite as a starting material. X-ray powder diffraction analysis indicates that a phase with Nasieon-like structure exists together with other phases in the composition range of x =0.1, y≤0.2 and x =0.2,y ≤0.2. AC impedance measurements show that the initial composition with x = 0.10, y = 0.10 possesses the highest ionic conductivity of 1.65 × 10^-5 S·cm^-1 at room temperature, while the sample with initial composition of x =0.20, y =0.10 has the best ionic conductivity of 6. 53 × 10^-3S·cm^-1 at 573 K and decomposes at 3.0 V.

Numerical Analysis on the Magneto-Elastic Stability of Current-Carrying Conductors: Aiming at Applications for the Tokamak System

A novel method for calculating the magnetic stiffness matrix was proposed for the numerical analysis of the magneto-elastic stability of complicated current-carrying structures aim- ing for application in the magneto-elastic behavior of the tokamak system. A code based on the proposed method was developed and applied to the numerical analysis of two typical current- carrying structures. The good consistency of the numerical and analytical results validated the proposed method and the related numerical code.

Study on Lithium Fast Ion Conductors of Li_(3x)La_(0.67-x) In_yTi_(1-2y)P_yO_3 System

Perovskite type lithium fast ion conductors of Li 3 x La 0.67- x In y Ti 1-2 y P y O 3 system were prepared by solid state reaction. X ray powder diffraction shows that perovskite solid solution forms in the ranges of x =0.10～0.12, y ≤0.2. AC impedance measurements indicate that the bulk conductivities and the total conductivities are of 1×10 -4 and 1× 10 -5 S·cm -1 at 25 ℃ respectively. The compositions have low bulk activation energies of 20 kJ·mol -1 in the temperature ranges of 298～523 K and total activation energies of 40 kJ·mol -1 in the temperature ranges of 298～623 K.

Studies on a New System of Lithium Fast Ion Conductors Based on Kaolinite and LiZr_2(PO_4)_3

Natural layered aluminosilicate Kaolinite Al 4[Si 4O 10 ](OH) 8 has been used as a starting material for preparing a new system of lithium fast ion conductors by high temperature(1073—1223 K) solid state reactions. X ray powder diffraction and a.c. impedance technique were used to characterize the compositions of the Li 1+2 x Al x Zr 2- x Si x P 3- x O 12 system. A single pure solid solution phase with R3c space group can be formed in the composition range of x ≤0 4. A specimen with x =0 3 possesses a maximum ionic conductivity which reaches up to 1 03×10 -2 s/cm at 723 K and the activation energy is 29 63 kJ/mol.

STUDY ON THE STRUCTURE OF IONIC CONDUCTOR FOR LiH-LiF-P_2O_5 GLASS SYSTEM

The system of LiH-LiF-P_2O_5 ionic conductor glass is prepared in neutral atmosphere and glass -forming region is given. The structure and coor- dination of glass are analyzed by IR spectra. Raman spectra and RDF(r). The result indicates that the (PO_4), (PO_3F) and (LiF_4) tetrahedra are basical structure units of glass network and the coordina- tion number of Li is 4. The coordination number of P is 4. The glass random network structure model is given. The study on structure shows that Li^+, H^- and partial F^- are charge carriers in glass system.

Numerical Analyses of Ice Jamming in Jacket Platform Conductor Array in Bohai Sea

Serious ice accumulating,pile-up and ice jamming occur around the conductor array of offshore jacket platforms during the winter every year in Bohai Sea,which could cause grave threats to the stability of platform structure,the safety of people and equipment,and even severer calamity.Therefore,the process of ice accumulation and ice jamming in the jacket platform area needs more concern.This study focuses on ice accumulation and jamming behaviors in the jacket platform conductor area by using a coupled two-dimensional hydro-ice dynamics model.A series of cases are conducted with different flow conditions,such as flow velocity,drifting direction and oscillatory flow.Through the simulation,the ice pile-up process is described and changes in ice-jamming thickness,ice pile-up location and ice pile-up volume are investigated.The differences in ice pile-up in the steady flow and oscillatory flow are analyzed.This study proposes a new approach to simulate the ice jamming process in the jacket platform conductor area,providing a reference for ice management on the platform.

Study on Load Bearing Characteristics of Novel Expandable Deepwater Drilling Conductor Based on Laboratory Experiment and Field Test

A novel expandable conductor was designed and applied in deep-water drilling to improve the vertical and lateral bearing capacity with a significant reduction of conductor jetting depth and soaking time. The vertical and lateral bearing capability of expandable conductors was depicted based on the ultimate subgrade reaction method and pile foundation bearing theory. The load-bearing characteristics of a laboratory-scale expandable conductor were analyzed through laboratory experiments. The serial simulation experiments are accomplished to study the bearing characteristics(vertical ultimate bearing capacity, lateral soil pressure, and lateral displacement) during the conductor soaking process. The laboratory experimental results show that the larger the length and thickness of expandable materials are,the higher the bearing capacity of the wellhead will be. During the conductor soaking process, the soil pressure around the three expandable conductors increases faster, strings representing a stronger squeezing effect and resulting in higher vertical bearing capacity. Furthermore, the lateral displacement of novel expandable conductor is smaller than that of the conventional conductor. All the advantages mentioned above contributed to the reduction of conductor’s jetting depth and soaking time. Lastly, the application workflow of a novel expandable deep-water drilling conductor was established and the autonomous expandable conductor was successfully applied in the South China Sea with a significant reduction of conductor’s jetting depth and soaking time. According to the soil properties and designed installation depth of the surface conductor, the arrangement of expandable materials should be designed reasonably to meet the safety condition and reduce the construction cost of the subsea wellhead.

Simulation analysis on microscopic discharge characteristics of the bipolar corona of a floating conductor

A floating conductor exhibits a bipolar corona phenomenon with microscopic discharge characteristics that are still unclear.In this study,a plasma simulation model of the bipolar corona with 108 chemical reaction equations is established by combining hydrodynamics and plasma chemical reactions.The evolution characteristics of electrons,positive ions,negative ions and neutral particles,as well as the distribution characteristics of space charges are analyzed,and the evolutionary flow of microscopic particles is summarized.The results indicate that the positive end of the bipolar corona initiates discharge before the negative end,but the plasma chemistry at the negative end is more vigorous.The electron generation rate can reach 1240 mol(m^(3) s)^(-1),and the dissipation rate can reach 34 mol(m^(3) s)^(-1).The positive ion swarm is dominated by O_(4)^(+),and the maximum generation rate can reach 440 mol((m^(3) s)^(-1).The negative ion swarm is mainly O_(2) and O_(4).The O_(2) content is approximately 1.5-3 times that of O_(4),and the maximum reaction rate can reach 51 mol(m^(3) s)^(-1).The final destination of neutral particles is an accumulation in the form of O_(3) and NO,and the amount of O3 produced is approximately 4-6 times that of NO.The positive end of the bipolar corona is dominated by positive space charges,which continue to develop and spread outwards in the form of a pulse wave.The negative end exhibits a space charge distribution structure of concentrated positive charges and diffused negative charges.The validity of the microscopic simulation analysis is verified by the macroscopic discharge phenomenon.

Alternative Solutions to Mitigate Problems due to Neutral Conductors Theft in MV （Medium Voltage） Power Distribution Systems

This paper aims at analyzing the impact of the neutral conductor absence at specific sections over the performance of the power distribution lines, and proposing alternative solutions to mitigate the problems caused by the neutral conductor theft. Simulations are made by the software lnterplan and show that the absence of neutral conductor at specific sections of power distribution lines may increase the neutral-to-ground voltages, which compromises the system＇s safety. The solution developed keeps the technical performance of the power distribution system at satisfactory levels, regarding the voltage profile, or, at least, close to the level before the neutral conductor＇s theft.

Numerical Analysis of the Influence of Turbulence Intensity on Iced Conductors Gallop Phenomena

Turbulence is expected to play a relevant role in the so-called conductor gallop phenomena,namely,the high-amplitude,low-frequency oscillation of overhead power lines due to the formation of ice structures and the ensu-ing effect that wind can have on these.In this work,the galloping time history of a wire with distorted(fixed in time)shape due to the formation of ice is analyzed numerically in the frame of afluid-solid coupling method for different wind speeds and levels of turbulence.The results show that the turbulence intensity has a moderate effect on the increase of the conductor’s aerodynamic lift and drag coefficients due to ice accretion;nevertheless,the corresponding changes in the torsion coefficient are very significant and complicated.A high turbulence intensity can affect the torsion coefficient in a certain range of attack angles and increase the torsion angle of the conductor.Through comparison of the galloping phenomena for different wind velocities,it is found that the related amplitude grows significantly with an increase of the wind speed.For a relatively large wind speed,the galloping amplitude is more sensitive to the turbulence intensity.Moreover,the larger the turbulence intensity,the larger the conductor’s vertical and horizontal galloping amplitudes after icing.The torsion angle also increases with an increase in the wind speed and turbulence intensity.

Research on Breeze Vibration Law and Modal Identification Method of Conductor Considering Anti-Vibration Hammer Damage

In the harsh environment,the structural health of the anti-vibration hammer,which suffers from the coupled effects of corrosion and fatigue damage,is significantly reduced.As part of the conductor structure,the anti-vibration hammer is rigidly attached to the conductor,effectively suppressing conductor vibration.The conductor’s breeze vibration law and natural modal frequency are altered damage to the anti-vibration hammer structure.Through built a vibration experiment platform to simulate multiple faults such as anti-vibration hammer head drop off and position slippage,which to obtained the vibration acceleration signal of the conductor.The acceleration vibration signal is processed and analyzed in the time and frequency domains.The results are used to derive the breeze vibration law of the conductor under multiple faults and propose an anti-vibration hammer damage online monitoring technology.The results show that the vibration acceleration value and vibration intensity of the conductor are significantly increased after the anti-vibration hammer damage.The natural frequency increases for each order,with an absolute change ranging from 0.15 to 6.49 Hz.The anti-vibration hammer slipped due to a loose connection,the 1st natural frequency increases from 8.18 to 16.62 Hz.Therefore,in engineering applications,there can be no contact to determine the anti-vibration hammer damage situation by monitoring the modal natural frequency of the conductor.This is even a tiny damage that cannot be seen.This method will prevent the further expansion of the damage that can cause accidents.

特高压电网不等高差短导线的受力性能

目前中国的特高压电网技术得到了快速发展。然而,工程中常由于忽视对导线受力性能的分析而酿成绝缘事故。根据导线两端挂线点的空间位置,其连接方式可分为等高差导线连接和不等高差导线连接。为此,本文提出了一种计算不等高差短导线端子在不同方向上受力性能的经验公式。通过改变挂线点之间的水平间隔距离、竖直高度差两个因素,开展了不同空间布局组合状态下的导线端子的受力特性分析,提出了可供设计参考的导线端部力学分析公式。结果表明经验公式具有良好的工程适用性。导线两端的受力特性不仅与环境荷载有关,与导线型号、两端竖直高度差、两端水平间隔距离等因素有关。

三相导线-相间间隔体系直流融冰热特性有限元及脱冰动力响应分析

为研究输电线路导线直流融冰非对称运行特性,以LGJ-400/50输电导线为研究对象,建立不同运行条件下的输电导线实体模型,采用COMSOL软件探究不同覆冰厚度对导线温度分布的影响,并对不同环境温度和不同风速对导线中心点温度变化进行分析,得到脱冰时刻导线温度作为初始条件施加,应用ANSYS LS-DYNA PrepPost非线性结构动力学模型,建立实际运行过程三相导线-相间间隔体系有限元模型,分析导线体系直流融冰非对称脱冰动力响应。结果表明,在采用不同融冰方案工况下,不同脱冰相数下导线体系最大脱冰跳跃高度不同,三相导线-相间间隔导线体系在融冰过程中相比单导线脱冰情况具有非对称性,依据间隔棒布置条件对导线体系脱冰动力响应影响规律,能够优化导线相间距进而保证直流融冰过程安全运行。

基于ABAQUS的输电线找形与分裂导线模拟研究

架空输电线是输电塔-线体系的重要组成部分,但由于几何非线性特征强,难以直接得到输电线的初始形态。基于ABAQUS有限元分析软件,提出更新形状法和更新张力法两种输电线找形方法,建立单导线模型作为算例进行分析与对比。研究结果表明,两种找形方法均具有很高的精确性,而在操作性和适用范围方面存在区别。由于新建输电线路的需求,分裂导线越来越多地被应用于输电线路中,考虑间隔棒与分裂导线间的耦合作用,提出一种分裂导线的模拟方法,可以实现分裂导线的精细模拟,并通过简化模型和精细化模型的动力特性对比,验证模拟的准确性。提出的输电线找形方法和分裂导线模拟方法可以为输电线路精确建模和分析提供参考。

浩吉铁路接触网防雷系统改造方案

接触网是电气化铁路的主要组成部分,均为露天架设、无备用,面临各种恶劣的气候条件,特别是雷击影响尤为突出,轻则引起绝缘子闪络跳闸,影响列车正常行驶;重则引起接触网断线事故,造成列车停止运行。因此,接触网防雷是接触网建设、运营需要重点考虑的因素。文章从既有铁路现状、防雷措施、防雷改造、避雷线安装注意事项等方面提出了既有线路接触网防雷改造方案,并通过方案实施,判断方案的可行性,供相关人员参考。

基于LSTM神经网络的牵引站电气设备耦联体系地震响应预测

铁路牵引变电站中,软导线-电气设备耦联体系具有较强的几何非线性。为提升系统分析效率,提出一种改进的软导线-电气设备耦联体系地震响应递归预测方法。基于长短期记忆(long short-term memory,LSTM)神经网络与Dropout防止过拟合技术搭建了LSTM神经网络预测模型。建立了充分考虑软导线对相邻设备的耦联作用的软导线-电气设备耦联体系理论分析模型。为验证预测模型的泛化能力,筛选出了41条在峰值、频谱和持续时间上具有较大差异的地震波。并按照递归方案,将选取的地震波以及软导线-电气设备耦联体系理论分析模型计算所得的位移响应,进行滑动切片处理,建立模型输入特征与输出响应标签的映射关系。在此基础上,利用该LSTM神经网络预测模型开展了软导线-电气设备耦联体系设备的地震位移响应预测,并采用多个评价指标进行较为全面的模型性能评估。研究结果表明:LSTM递归预测模型具有良好的地震响应预测性能,搭配Dropout技术能够有效防止模型训练过拟合,提高模型适应能力。对于差异较大的地震波数据,均能够快速预测出误差较小、相关度较高的地震响应,具有较好的准确性、高效性与泛化能力。所提方法能够较高效准确地预测任意时刻的软导线-电气设备耦联体系地震响应,为铁路牵引变电站抗震设计提供新的研究思路。

大风区接触网线路参数对附加导线舞动的影响

针对大风环境下兰新高速铁路接触网附加导线发生剧烈舞动以及线间放电的现象,依据接触网附加导线结构特点,建立了附加导线有限元计算模型,并对附加导线进行找形计算。采用谐波叠加法模拟接触网附加导线处的随机风场,并对导线模型施加风荷载,利用无条件稳定Newmark法以及荷载增量法,分析接触网线路参数对附加导线舞动及线间距离的影响规律,并给出相应的舞动防治措施。结果表明:40 m及更小档距对导线在低风速及高风速下的舞动均有明显的抑制效果;将附加导线运行张力提高至6.5 kN,导线阻尼比提高至1.5%及以上能有效降低两条导线的舞动剧烈程度;接触网附加导线的档距过大,运行张力及阻尼比过小,将导致导线舞动时悬挂点张力过大,易引起导线掉线、断线等事故;随附加导线档距减小、运行张力及阻尼比增大,线间最小距离呈递增趋势;不同线路参数下(档距、运行张力及阻尼比)附加导线舞动时线间最小距离均随风速增大出现减小趋势。本研究可为兰新高铁大风区段接触网附加导线舞动及线间放电的防治提供有效的理论依据。