基于混合输电线路下故障测距方法研究

为了提高混合输电线路的故障测距效率,提出了一种基于混合输电线路下故障测距方法。首先对混合输电线路的故障行波传播特性进行深入分析,包括反射特性和折射特性,并建立混合输电线路故障测距模型,通过搭建仿真模型对线路上不同位置出现故障的情况进行模型。结果得到：在混合输电线路上不同位置出现金属性直接接地故障和经60Ω的过渡电阻接地故障时,通过对两端故障相电压和相电流的采集,利用所提方法能够较为准确判断故障点所在区间,且距离计算最大误差为120m。进而表明所提方法有效弥补因线路长度与行波传播时间不同步所引起的误差,该对混合输电线路故障更好的定位和测距有重要意义。     

高压电力电缆配电线路故障在线检测方法研究

为了解决高压电力电缆配电线路供电过程发生接地故障时,配电线路无法正常供电的问题,提出一种基于行波故障测距原理的高精度、快速度的线路故障在线检测方法。检测已知故障行波速度、未知故障行波速度以及高压电力电缆配电线路故障发生位置,通过在高压电力电缆配电线路故障位置处安装电容器向故障回路放电,故障回路包括电容器、配电线路和故障点过渡串联电阻,通过该回路的特征频率和衰减系数故障位置线路两端的电阻,得到线路故障信息。仿真实验结果表明,该检测方法具有较高精度。     

基于改进双端法的高压交流输电线路故障定位

现有输电线路行波故障测距方法由于受行波波速的不确定性以及输电线路弧垂的影响,容易出现较大的定位误差.为此,提出了一种无需波速和线路长度整定的线路故障行波定位方法.利用线路两端的行波信号检测装置记录故障电压行波波头到达时间,同时根据电压行波折反射过程中的传播路径列出关于距离、速度和时间的方程组,经过数学变换可以消去线路弧垂的影响,并在线路上实时在线测量行波速度.用PSCAD软件对双端结构的输电线路进行了仿真,实验结果表明该方法具有好的适应性,在实际测距中对线路电气参数依赖性低,不受故障类型,故障位置和过渡电阻等因素的影响,定位误差较小,原理简单,具有较高的准确性和良好的适用性.     

高压直流输电线路保护与故障测距原理研究

直流输电线路保护与故障测距是高压直流输电工程保护系统的重要组成内容,承担着快速检测与排除线路故障的工作任务,其运行性能是否良好,直接决定着高压直流输电系统和电网的运行安全。鉴于高压直流输电线路保护与故障测距的重要性,本文基于大量文献资料对高压直流输电线路保护与故障测距原理进行了深入分析,夯实相关的理论基础,提高理论水平,进一步发挥对高压直流输电线路保护与故障测距工作的指导作用,使相关工作有序、高效展开。     

基于暂态电流的高压输电线的故障检测

针对高压输电线故障存在检修困难、故障点定位误差较大和易受外部因素影响等问题,本文根据行波传输理论以故障电流行波为测量对象,提出一种基于暂态电流的高压输电线路单端故障测距算法。现以某区电网高压输电线路故障为例,利用MATLAB构建仿真模型进行仿真。由仿真结果可以看出：所采用的故障测距算法不仅计算简单,而且测距精度较高。     

高压输电线路的故障测距方法探讨

高压输电线路是电网的重要组成部分,对高压输电线路的准确故障测距是保证电网安全稳定运行的重要技术措施。本文对高压输电线路故障测距中常用的方法进行了分析,希望能够为相关工作的开展提供一定的支持。     

高压输电线路故障测距方法的应用

高压输电电网在快速发展的同时,其故障问题随着增多。高压输电线路以其不稳定性给用户带来一定的麻烦。如何及时发现故障并正确解决是企业在发展过程中的主要任务。目前,相关行业多采用故障距离测试法检查高压和超高压输电线路的故障,由于这种方法具有高效性和多样化的特点,因此文章从故障分析法、行波法及智能化测距法三个方面具体分析了高压输电线路故障的测距方法。实践证明,高压输电线路采用故障测距法检查故障具有可行性,有助于促进我国电网的可持续发展。     

输电线路杆塔接地状态在线监测技术研究

采用人工方式监测输电线路杆塔接地状态时,存在测量时间较长,无法及时监测故障点的弊端,因此研究一种输电线路杆塔接地状态在线监测方法。分析输电线路杆塔接地在线监测原理,获取故障发生时接地电位与入地电流,修正不同形状接地装置,利用平均电位求出输电线路杆塔接地电阻,再计算加入埋深与降阻剂的输电线路杆塔接地装置电阻,以及考虑4个基础接地电阻并联得到的最终接地电阻;故障检测器中设定电流数值,若通过该输电线路杆塔工频接地电流比设定电流大,则故障指示器提示故障,接地电流短路时,依据差动电路原理通过传感器确认故障杆塔位置。实验结果表明,该方法可准确检测出输电线路杆塔接地电阻与故障点准确位置,监测电阻误差均低于0.1Ω,监测效率高。     

传输线参数测试方法研究

传统的传输线参数测试方法是终端开路、短路测试。对于高压输电线路,终端直接短路时,短路电流较大,对电力设备有损害。本文提出了在线路正常运行时利用全球定位系统（GPS）提供的时间为基准,对传输线两端的电压、电流进行同步采样和测量。根据牛顿—拉夫逊法对传输线方程进行迭代计算可以得到传输线参数。通过Matlab仿真计算验证了该方法是有效的。     

架空输电线路的故障测距方法综述

对高压架空输电线路进行准确的故障测距是保证电力系统安全稳定运行的有效途径之一。为此,文章比较全面地介绍了国内外在此方面的发展历程和研究现状。根据各测距算法采用的原理不同,将现有的各种测距算法分为行波测距、单端测距和双端测距三类,然后逐类对各种算法的理论基础和应用条件上进行了分析、对比和讨论,并在此基础上总结得出了各测距算法的优点及存在的问题,指出了每种测距算法的适用范围和应用局限性。最后,对高压架空输电线路故障测距的研究及应用前景进行了展望。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.