一起500kV主变压器非典型故障跳闸的原因分析及整改

对一起500k V主变压器故障跳闸起火事故进行分析,合理推断事故原因是主变高压侧油中均压罩向套管升高座发生放电导致绝缘击穿,并针对此项罕见的非典型主变故障跳闸原因,提出了为均压罩加装绝缘屏蔽的整改反措建议,以便提升500k V主变压器安全稳定运行水平。     

一起10kV开关越级跳闸事故分析

本文从变电站运行工作的实际出发,对一起由线路故障发展为主变低压侧开关越级跳闸的事故进行分析,指出保护动作越级跳闸的关键原因,并根据分析提出了问题的解决方案,并探讨了在日常运行工作中对此类问题的预防措施.     

浅谈500kv变电站误跳闸的原因及预防措施

本文结合工作实践,以某市500kv变电站主变发生误跳闸的事故为例,通过现场调查的主变本体状况、保护动作情况以及故障录波数据,分析了主变跳闸的原因,并提出了相应的预防措施。     

故障录波装置的改进设计及解析

随着电网供电稳定性要求不断提高,承担电网输送供电的开关站设备的质量、安全性能及平稳运行关系重大,特别是一些大型开关站和枢纽站的安全稳定运行尤为重要,近年来该类设施在运行中出现的一些问题,造成断路器越级跳闸或部分断路器故障跳闸的事故,导致区域性大面积停电,严重影响了供电的可靠性.故障录波装置能够记录断路器跳闸前后的波形,根据波形分析断路器的跳闸原因,并查找故障,可见故障录波装置对断路器运行起着重要的监控作用.本文主要针对目前开关站故障录波装置存在的一些问题进行分析,并提出相应改进设计的措施.     

新型柔性碳元素接地体的应用及安装

输电线路是电力系统的基本组成部分,频繁的雷击跳闸事故一直是输电线路面临的最主要自然灾害故障.从输电线路所处的地形及气候环境来看,雷电作用下输电线路出现一定的雷击跳闸难以避免.安康电网地处陕西省南部秦岭巴山区域,当地气候多雨多雷,输电线路雷击跳闸率占总跳闸率的60%-70%以上.长期运行经验表明,杆塔接地电阻偏大是引起线路反击跳闸的主要原因.低阻值、长期稳定的输电线路杆塔接地网是减少输电线路雷击事故、维护电力设备安全稳定运行的重要电力装置,功能良好的接地装置是电力运行系统的基本组成部分.     

110kV变电站线路保护越级跳闸事故的思考

110kV变电站线路保护越级跳闸现象会造成严重的安全事故,甚至对人们的生命健康造成威胁.现阶段,这一事故的发生十分频繁,严重影响了变电站的正常运行,因此,需要对事故的发生原因进行深入的探究,以从根本上杜绝线路保护越级跳闸现象的发生.本文主要对变电站线路保护越级跳闸事故进行分析,深入探究其发生的主要原因,从而提出相应的解决措施,以保证变电站的安全、高效运行.     

可调速驱动跳闸现象的诊断

可调速电动机的电闸经常跳闸,切断电源,不仅讨厌,查找原因也属不易。跳闸断电使产品报废,增加生产成本,浪费资源。变更跳闸电子,从经济上说无可非议,但是这不是根本的解决办法。电动机多次跳闸预示着将要发生大的故障,必须进行校正性测量,排除故障以期永久性地解决问题。大多数现代化调速电动机装有故障监视器,一有故障就跳闸,切断电源以保安全。检查4种基本     

变电运行中的跳闸故障及其处理技术

变电运行是电网运行的重要组成部分,如果在变电运行的过程中出现故障,那么就会给该地区的居民带来巨大的损失,尤其是出现跳闸问题,就会影响到用户的正常用电,甚至会瘫痪整个供电系统,进而使较大范围的地区不能用电,就会严重影响人们的生活和工作.一般情况下,人为和设备因素是导致变电运行出现问题的原因,当设备出现问题跳闸后,必须及时查明故障的原因、故障影响的范围,并采取与之对应的解决措施,保证能够为用户正常的供电.本文主要对跳闸故障概述以及针对跳闸故障的处理技术进行了详细的分析.     

电气化铁路隧道接触网跳闸及设备烧损原因与预防

铁路供电专业经常发生隧道接触网跳闸故障,针对这一现象,本文分析其跳闸常见原因和附近设备烧损原因及相关预防措施.     

35kV主变差动保护误动作事故分析

文章介绍了35kV上马变电站10kV线路故障引起1#主变差动保护误动作跳闸事故,通过调阅现场保护装置事故记录、审查设备定值计算、保护装置特性试验、主变压器差动回路二次接线及电流互感器进行了全面的分析,指出了保护动作的原因并采取了纠正措施,保证了电网的安全稳定可靠运行。     

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.