输电线路长度和参数的校正方法

提出了一种线路长度和参数的在线估计方法,利用区内出现的缺相运行情况对线路正、负、零序参数和线路长度同时进行校正。该方法适用于装设单相自动重合闸的架空输电线路,利用现有的硬件设备,可以有效地削弱线路长度和参数变化对测距精度的影响,对于故障测距和线路保护均具有较重要的意义。     

500kV双回路垂直排列紧凑型线路应用分析

通过500 kV双回路垂直排列紧凑型线路电气性能计算分析,提出在城镇规划地区和房屋密集地区采用垂直排紧凑型线路的建议。该措施可有效降低地面电场强度,缩小线路走廊宽度,减少房屋拆迁面积,提高线路输送容量,利于保护环境,具有良好的经济效益和社会效益。     

Design of transmission line filters and matching circuits using genetic algorithms

A method for designing microwave filters and impedance matching circuits using transmission lines is presented. Transmission line filters with shunt‐connected open circuit stubs and continuously varying transmission line matching circuits are described in detail. The proposed method is based on genetic algorithms and can effectively be applied to various filter and matching circuit design problems without increasing theoretical and computational complexity. Design examples are provided, and the proposed method is demonstrated to be effective in designing transmission line filters and matching circuits. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

以人工传输线延时的双路高电压触发器

将多路高电压触发器的运行模式从"先延时后触发"改变为"先触发后延时",并用人工传输线代替集成电路芯片构成时延电路,这大大提高了多路高电压触发器的抗电磁干扰能力。经过上述改造后,一台双路高电压触发器成功地被用来触发两台雷电波大电流发生器,使它们先后相隔约100μs放电。     

Theory on asymmetrical coupled‐parallel‐line transmission and reflection zeros

This paper treats an innovative methodology on the synthesis mechanism of the coupled‐parallel‐line (CPL) transmission zero (TZ) and reflection zero (RZ). The CPL structure under study is configured as a reflection type distributed arbitrarily loaded stub circuits. On the basis of the equivalent Z‐matrix analysis, the CPL input impedance theoretical model is established. Mathematical analysis is performed to predict accurately the TZ and RZ frequency shifts in function of the CPL physical parameters. The input impedance behavioral model in function of asymmetrical CPL load parameters is determined. The TZ and RZ existence conditions are established. Then, the characteristic equations illustrating the TZ and RZ fundamental formulas in function of the CPL coupling coefficient and characteristic impedances are examined. Furthermore, innovative graphical representations of the TZ and RZ existence conditions in function of the CPL parameter ranges are explored. The developed CPL model was validated with different cases of simulated microstrip proof of concept. As expected, a good correlation between the TZ and RZ frequency shifts from the analytical calculations and simulations is obtained. The developed CPL model is useful for the TZ and RZ frequency shifts fast monitoring during the Radio Frequency (RF)/microwave circuit design phase. Copyright © 2017 John Wiley & Sons, Ltd.     

A generalized CAD model for the full‐wave modelling of microstrip line and its regular and irregular discontinuities

In this paper we present a new theoretical model for the modelling of the microstrip line as well as two types of discontinuities: regular (open end, step, bend and T‐ and cross‐junctions) and irregular (stub and bent‐stub). The two‐dimensional exact dyadic Green function of a grounded dielectric slab has been used with the Galerkin's technique. The subdivision of the discontinuity in a network of juxtaposed unit cells, characterized by their own longitudinal and transversal current distributions, allowed the treatment of a large class of irregular discontinuities in addition to the regular discontinuities. The obtained results have been commented and compared with those of different approaches and with experimental results where a good concordance has been observed. Copyright © 2006 John Wiley & Sons, Ltd.     

A new decoupling method for double‐circuit transmission lines with asymmetrical parameters

The six‐sequence component method is widely used in short‐circuit calculation of double‐circuit lines. However, this method can be used to decouple only two parallel transmission lines whose parameters are exactly the same. In this paper, a new sequence component method is introduced to deal with the lines whose parameters are not exactly the same. Mutual impedances between phases of the same line are decoupled first, and then the zero‐sequence mutual impedances between different lines are decoupled. Six new independent components are obtained after decoupling. System impedances are modified based on the relationship between voltages and currents of the new sequence components and the traditional sequence components. According to the boundary conditions of the faults, the characteristics of new sequence components are studied, and the corresponding sequence networks are discussed. According to the combined sequence network, new sequence currents can be calculated, and the phase currents can be obtained easily from the new sequence currents by a transformation matrix. PSCAD simulation results demonstrate that the short‐circuit calculation method proposed in this paper is appropriate and practical to deal with the two parallel transmission lines with different parameters and partially coupled transmission lines. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

基于分布参数模型的混合输电线路精确测距及重合闸方案

华东镇海—舟山500kV线路工程采用复杂的电缆-架空线混合输电线路,发生故障时无法准确对故障位置进行定位,且现有的重合闸方案无法实现自动识别架空线路故障并投入重合闸。文章提出一种基于分布参数模型的混合线路故障测距方案,方案采用正序故障分量,利用混合线路各段准确参数,分别采用线路两侧电气量计算沿线各点的电压有效值。根据两侧电气量计算的故障位置电压有效值相等的特点,对故障位置进行准确计算。且针对实际工程对重合闸的需求,提出一种故障位置区段定位方法。该方法通过比较用两侧电气量计算的电缆和架空线交界处的电压有效值对故障所在区段进行定位,以实现故障点位于电缆线路时不重合,故障点在架空线时重合闸。仿真结果表明,采用华东镇海-舟山500kV线路工程各段准确参数,各故障位置、各故障类型测距误差均不大于2.5%或±1km,测距结果不受过渡电阻影响,且可实现自动识别架空线故障并投入重合闸。     

基于分布参数模型的输电线路相间距离保护

采用分布参数建模,利用保护安装处的测量电压和测量电流计算等效故障点电压,根据保护区外故障时等效故障点电压相量在测量电压和补偿电压相量一侧和保护区内故障时等效故障点电压相量在测量电压和补偿电压相量之间这一故障特征构成判据,提出一种适用于高压/超高压/特高压输电线路的相间距离保护新方法。该方法有良好的耐故障电阻和抗负荷电流影响的能力,具有良好动作灵敏度。该保护原理适用于距离保护I段,具有良好的保护范围。EMTDC仿真结果验证了该保护原理的正确性和有效性。     

同杆并架双回输电线路感应电压的计算

分析了两回线路同杆并架时停运线路上感应电压产生的原因,并进行了仿真计算,分析了接地线位置和接地电阻大小,导线排列,运行线路载荷及投切操作,杆塔接地电阻等因素对感应电压的影响。得出了接地线位置和其电阻的大小是影响停电线路上感应电压大小的重要因素的结论。     

基于断路器重合闸的柔性直流输电线路单端故障测距方法

高压柔性直流输电采用架空线路,运行环境复杂,难以避免故障.快速准确的故障定位可以缩短故障清除时间,对于快速恢复供电十分重要.现有测距算法依赖暂态波头辨识,受到干扰后测距精度会下降.针对上述问题,在线路分布参数模型基础上,在时域中通过电报方程计算线路沿线分布的电压和电流,进而根据故障点处电阻值相对稳定这一特性构成测距判据...     

分段输电线路求解整段参数计算理论研究

输电线路工频参数的准确及时获得对电力系统至关重要,否则可能会给电力系统带来恶劣的影响,甚至造成重大电力事故的发生。目前国内外针对线路参数理论计算通常采用传统公式。针对中、短输电线路施工或运行中分段参数与整段参数的求解问题,本文以某220kV双回线路为例,验证得到传统方法在求解正序参数上可以很好应用,但在零序参数求解上存在较大误差。为提高零序参数理论计算的准确性,本文首次提出将输电线路划分为整的参数理论计算公式及其等值稳态电路模型,即对各分段输电线路进行参数测试,然后经过科学计算得出整段线路参数,为输电线路参数测量提供了一种快速有效的方法。经实例计算验证该模型在零序参数求解上相对传统模型而言误差更小,可用于中短输电线路的参数计算,并进一步提出了该模型的改进措施。     

基于同步相量测量的线路参数在线计算

提出一种基于同步相量测量的输电线路参数在线求解方法。该方法以分布参数线路模型为基础，在已知线路两端同步电压和电流的条件下精确求解出线路特性阻抗、传播常数、单位长度电感和电容。仿真结果验证了该方法的正确性。     

双回耦合输电线路的零序参数在线测量

分析了双回耦合输电线路的结构,建立了其零序分布参数电路模型和"双Π形"零序集中参数电路模型;将增量法与"双Π形"电路相结合,提出了零序集中参数在线测量算法;推导了零序集中参数与分布参数间的转换关系,提出了零序分布参数在线测量算法;对不同长度的500 kV双回耦合输电线路进行仿真实验。仿真结果表明,所提出的电路模型及在线测量算法适用于电力系统的零序参数在线测量。     

基于双端不同步采样数据的高压输电线路故障测距

提出了一种基于双端不同步采样数据的高压输电线路故障测距算法。该算法考虑了线路的分布参数特性,利用线路双端电压和电流量进行故障测距,从而保证测距不受过渡电阻的影响。对于不换位三相线路,采用模分量法,使相互耦合的相空间三相线路解耦为相互独立的模量。为了避免求解导数的复杂性,该文采用Powell方向加速法进行求解。仿真计算表明,算法对整个线路长度区间内的任何故障点都能精确测距。     

特高压输电线路分布式故障诊断系统研制及其关键技术

分布式线路故障诊断系统作为特高压输电线路故障位置定位服务的关键产品,对电力系统的安全、可靠与经济运行具有重要意义。结合实际系统的研制与应用,提出了一种基于分布式安装的线路监测终端、监测运维中心站和移动终端应用服务于一体的新型故障诊断服务系统。阐述了产品与系统的关键实现方案,并提出了基于监测终端的供能及其管理、高速采样及同步、时间同步及坐标定位、行波启动及识别处理技术,基于监测运维中心站的双机冗余和数据安全隔离、测距和故障识别、GIS信息与微气象服务技术以及移动终端App安全服务等自主关键技术。所述系统产品顺利通过国家权威检测机构组织的测试与认证并在西部特高压交流1 000 kV输电线路上挂网运行,取得了稳定可靠运行的实际效果。     

基于分布参数线路模型的精确故障测距算法

为消除负荷电流和线路模型不准确给双端量故障测距带来的影响,提出一种基于分布参数线路模型的精确测距算法。算法以均匀传输线的波动方程(长线方程)为基础,利用线路两端电压、电流的正序故障分量以及线路正序参数直接计算故障距离。算法无需故障类型判别,不受系统阻抗、故障电阻、负荷电流以及分布电容的影响。基于EMTP的数字仿真结果验证了该算法的正确性和高精度。     

Generalized non‐uniform transmission‐line models for local radiation from microstrip bends in MMICs

Although microstrip bends in high‐speed digital MMICs have been widely investigated for the past two decades, their local radiation characteristics rather than their reflection characteristics have not been completely explored yet. In this paper, the generalized non‐uniform transmission‐line equations are used in analysing the microstrip bends including their local radiations. In our new models, the whole structure of a bend is regarded as a non‐uniform transmission line that is totally governed by the generalized non‐uniform transmission‐line equations. Except for analytical simplification and broad bandwidth performance, the new analysis could indicate where the strongly local radiations along a bend structure come from. Copyright © 2003 John Wiley & Sons, Ltd.     

输电线路零序参数的实用计算方法及系统

基于对输电线路参数计算方法的理论推导,分析影响输电线路参数工程计算精度的主要因素.针对输电线路沿线各段土壤电阻率变化较大且不易准确获取的问题,提出根据同一线路走廊内已投运线路实测参数反推沿线等效电阻率的方法;针对输电线路的局部同塔、局部平行及杆塔多样性特征,提出采用分段计算和杆塔参数简化处理方法;通过研究地线不同接地形...     

Hyperreal transients on transfinite distributed transmission lines and cables

A prior work showed how non‐standard analysis could be used to derive hyperreal transients in transfinite electrical networks containing lumped inductors, capacitors, resistors and sources. In this work, hyperreal transients are derived for transfinite electrical networks whose parameters are distributed. In particular, explicit expressions are derived for hyperreal transients on uniform transmission lines and cables that ‘extend beyond infinity’ transfinitely. This requires a substantially altered technique as compared to the prior work. The present one uses a different kind of truncation procedure that reduces the transfinite line or cable to a conventionally infinite one and then expands the latter in steps to ‘fill out’ the transfinite line or cable. Copyright © 2003 John Wiley & Sons, Ltd.