BJJ-660矿用隔爆型低压快速检漏继电器

针对目前煤矿井下普遍采用由三相电抗器、零序电抗器等组成的低压检漏继电器在电网发生漏电或人身触电事故时所存在的动作速度慢、补偿效果低等问题 ,给出了一种新的设计电路     

一种矿用低压漏电保护装置设计

针对基于零序功率方向选线原理的煤矿低压电网漏电保护装置可靠性不高的问题,给出了一种矿用低压漏电保护装置软硬件设计方案。该装置根据零序电抗器并联电阻接地系统发生单相接地故障时零序电流与零序电压相位差在非故障支路与故障支路中的差异性实现故障选线。仿真及试验结果表明,该装置不受电网中零序电抗器补偿的影响,发生单相接地故障时能够快速、可靠动作。     

线路断线引发多个110kV变电站失压原因分析及反措建议

介绍一起导致多个110kV变电站失压的事故。事故的起因是一条110kV线路A相线夹脱落，导致该线路缺相运行，使得继电保护装置和安稳系统先后动作，随即造成多个110kV变电站相继失压。分析计算表明，采取综合反事故措施，可以减小此类事故的停电范围。     

基于带并联电抗器的大型火电机组核相新技术研究

针对出线侧带并联电抗器的大型火电机组进行并网核相试验时遇到的特殊问题,提出了以发电机作为核相电源,进行两待并系统核相的新方法。对试验方案进行仿真模拟,对试验过程中各电量的变化进行考查,并对各设备保护的定值整定和投入进行论证。最后在核相试验过程中采取综合措施顺利解决励磁系统参数配合问题,圆满完成核相试验。     

超/特高压输电线路单相接地故障特性研究

超/特高压输电线路发生单相接地故障后.将采用单相自动重合闸.在合闸前区分瞬时性故障和永久性故障,对实现自适应重合,防止电力系统又一次遭受故障的冲击具有重要意义.超/特高压输电线路可分为带并联电抗器和不带并联电抗器两种方式,文中对两种方式下发生单相接地故障时故障相与非故障相之间的耦合进行了分析.线路不带并联电抗器时,瞬时性与永久性故障时故障相电压的本质区别为是否含有电容耦合电压,带并联电抗器时为恢复电压中是否含有自由频率分量.最后给出了1条750kV的输电线在MATLAB/SIMULINK平台上的仿真结果.验证了理论分析的正确性.     

10kV配电变压器低压桩头处渗油原因分析及应对措施

本文从10kV配电变压器安装和运行等环节分析了其低压桩头处渗油问题,并分别对其渗油原因进行分析,从而提出减少10kV配电变压器低压桩头处渗油发生的应对措施,以保证10kV配电变压器正常运行。     

一起500kV线路高压并联电抗器异响原因分析及处理

以一起500kV线路电抗器投运过程中产生异响为例,详细记录了异响故障处理过程,分析了电抗器产生异响的原因,提出了处理此类问题的有效手段。根据红外测温、绝缘电阻测试、油色谱离线分析测量等方法判断异响是否来源于本体内部;根据振动测试、噪音测试及设备运行情况判断是否异响来源于设备外部故障。通过多种检测方法及综合分析,发现异响来源是由于电抗器高压套管均压环内有金属焊接残留物和本体零部件的松动造成。根据此起500kV线路电抗器异响的故障分析与处理方法,总结了设备检修维护的可靠措施,并提出了故障诊断的有效手段,对运行人员进行故障初判具有一定的参考意义,有利于检修人员采取对应的措施,避免盲目检修。     

整流、电炉变压器故障的判断和处理

金川集团有限公司现有整流变压器42台,电炉变压器26台,在设备运行过程中,发生的故障频率较高、给金川集团公司的生产带来极大损失。其主要故障有:低压侧(阀侧)发生短路、调压绕组短路、电抗器短路引起变压器故障、有载开关故障引起变压器短路及油水冷却器漏水引起高压绕组短路故障。本文就变压器故障后、进行的事故检查和处理进行阐述,并分析了运行状态出现的几点问题。     

10kV高压开关柜烧毁事故分析

由于10kV高压开关柜长期温升超标而加速了柜内设备绝缘的老化，导致柜内10kV真空断路器绝缘拉杆性能下降而发生单相弧光接地，而柜内10kV三相限压保护器又由于选型不当而在暂时过电压作用下发生爆炸，引起相间短路，进而扩大了事故范围。     

煤矿井下低压电网故障闭锁的作用及设置

文章在分析煤矿井下发生火灾和瓦斯爆炸等事故的原因和各种故障闭锁功能作用的基础上,提出了一种井下低压电网装设故障闭锁的设计方案,详细介绍了漏电闭锁、短路闭锁和断相闭锁3种故障闭锁的设置情况,并给出了3种故障闭锁的故障预测及故障闭锁方法、电路及其工作原理。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。