高压电缆局部放电检测方法的研究

高压电缆局部放电检测系统的开发涉及到高压绝缘和高压试验等技术,局部放电检测是通过状态监测发现故障隐患,采取有效手段进行处理,降低供电系统运行风险,提高供电设备的运行效率,保证电力系统的安全性和稳定性。     

基于局部放电检测技术应用于配电开关柜的研究

开关柜的运行状态对电力系统供电可靠性具有重大影响。局部放电检测是反映开关柜绝缘状况的有效手段,利用不同放电模型模拟构造分析对于密闭的高压开关柜及相关设备的在线监测.针对高压开关柜由于在设计、制造、安装和运行维护方面存在着不同程度的问题,运用超声波原理对配电高压开关柜进行在线测试,根据放电类型能量的释放形式不同、各种检测方法的实用性与灵敏度也存在差异,在对开关柜局部放电检测过程中,综合应用各种不同类型的局放检测手段,根据不同测试波形及时发现问题,及时制定检修计划。     

超声法在检测高压开关柜内局部放电的应用

高压开关柜是电力系统中的关键设备之一,其内部电气元件分布繁多、排列紧密、绝缘裕度很小,易出现局部放电现象。为此以准确定位局部放电的位置为目的,提出了基于梯度收缩法的超声波定位算法,具体介绍该方法的基本原理、检测方法和判断结果。将此算法用于某企业的35 kV真空开关柜局部放电检测中,检测结果表明,该方法对高频干扰下的局部放电现象的检测更为精确有效,也为高压开关柜的故障检测以及安全运行提供了技术依据。     

高压开关柜局部放电检测技术的研究

高压开关柜是电力系统中非常重要的电气设备,其内部发生的局部放电会对开关柜乃至整个系统造成严重危害。文中介绍了适用于高压开关柜内的局部放电检测技术,并提出了基于这种技术的故障分析和判断方法,有助于及时有效地发现故障隐患,保障高压开关柜的安全运行。     

船舶高压电气设备局部放电模式快速识别研究

船舶高压电气设备局部放电严重影响电气设备的正常运行与船舶安全,但是不同类型的局部放电在放电过程产生的超高频电磁波信号存在显著差异,需要根据其电磁波信号进行模式识别,而传统的检测方法无法适应船舶强电磁干扰、高频机械振动噪声的恶劣环境。为此,本文设计了可以快速进行船舶高压电气设备局部放电模式快速识别的方法。该方法根据船舶高压电气设备超高频电磁波信号的特点,提取四种典型局放信号以及待测信号的特征值向量,通过计算模式识别可信度因子R,实现对待测局放信号的快速准确识别,试验测试表明该方法能够快速识别船舶高压设备局部放电类型,提升了船舶高压设备的运行可靠性。     

高压开关柜局部放电检测设备的特性分析

阐述高压开关柜局部放电检测设备特性保护中的问题,探讨高压开关柜中的局部放电检测方法,包括暂态地电压检测法、特高频检测法、超声波检测法的应用。     

高压开关柜局部放电检测分析

高压开关柜的安全可靠运行直接影响整个变电站的供电可靠性,对开关柜进行局放检测显得尤为重要。本文主要分析了检测高压开关柜局部放电的TEV方法与超声波方法的原理及检测方法。利用TEV与超声波相结合的方法进行了局部放电源的定位,经验证该方法精确度较高,对局放检测有一定的实用价值。     

基于超声和LabVIEW局部放电在线监测系统的研制

局部放电是使高压电力设备绝缘损坏的一个重要因素,为确保其安全、可靠运行,对高压电力设备进行在线监测至关重要.该文主要研究开发一种基于超声法和虚拟仪器的局部放电实时在线监测系统,基于4个声发射器检测局部放电源超声波信号,通过时域和频域分析,研究局部放电的超声信号特性,为故障诊断提供数据共享;采用虚拟仪器技术,实现本系统人机界面化,再结合后台数据库,达到多功能、多通道的实时监测.该系统的应用有利于发现绝缘故障的早期征兆,是诊断绝缘故障的一种有效方法.     

浅议110kV高压电抗器超声波局部放电检测

我国电网的发展日新月异,多台110 k V高压电抗器也得到了广泛的应用,但在这应用中也产生了许多的问题,因此需要有针对性地对其进行超声波局部放电检测。本文通过分析超声波技术的应用及用其来检测高压电抗器,结合青海电网实际浅议了110k V高压电抗器超声波局部放电检测。     

电力电缆局部放电信号的检测技术

电力电缆在长期运行后,电缆绝缘会发生老化乃至产生局部放电,局部放电信号的检测对于电缆绝缘状态的评判具有重要的参考价值。本文对电力电缆局部放电的检测技术进行了总结,分析了电缆局部放电检测中常见的干扰及其种类,提出了软件及硬件两方面的去噪措施。     

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.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

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.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

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.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

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.     

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.