Development of cable fault location method using fiber optic distributed temperature sensor

When ground-fault problems occur on a cable line, immediate fault location and restoration are required. Therefore, various new methods to locate the fault point instantaneously have been investigated to replace such conventional methods as the Murray loop method and the pulse radar method [1]. These methods require a long time to locate the fault point. One possible fault location method is to sense the temperature rise following a ground fault using a fiber optic distributed temperature sensor. Application of this method was found feasible through sensing the temperature rise at a ground-fault test using a thermocouple as a temperature sensor with test cables [4]. A power/optical composite cable was prepared experimentally and after verifying its thermal mechanical performance, the temperature rise at an incidence of a fault was determined and the anticipated performance was demonstrated in a ground-fault test. This article describes the outline of the test.     

Application of the blind source separation method to feature extraction of machine sound signals

As the result of vibration emission in air, a machine sound signal carries important information about the working condition of machinery. But in practice, the sound signal is typically received with a very low signal-to-noise ratio. To obtain features of the original sound signal, uncorrelated sound signals must be removed and the wavelet coefficients related to fault condition must be retrieved. In this paper, the blind source separation technique is used to recover the wavelet coefficients of a monitored source from complex observed signals. Since in the proposed blind source separation (BSS) algorithms it is generally assumed that the number of sources is known, the Gerschgorin disk estimator method is introduced to determine the number of sound sources before applying the BSS method. This method can estimate the number of sound sources under non-Gaussian and non-white noise conditions. Then, the partial singular value analysis method is used to select these significant observations for BSS analysis. This method ensures that signals are separated with the smallest distortion. Afterwards, the time-frequency separation algorithm, converted to a suitable BSS algorithm for the separation of a non-stationary signal, is introduced. The transfer channel between observations and sources and the wavelet coefficients of the source signals can be blindly identified via this algorithm. The reconstructed wavelet coefficients can be used for diagnosis. Finally, the separation results obtained from the observed signals recorded in a semi-anechoic chamber demonstrate the effectiveness of the presented methods .     

环缝错边容器的有限元分析与容限探讨

采用有限元方法对 1台封头与筒体具有较大错边量的容器进行了应力分析 ,得到了错边区域的应力分布状况 ,并对其进行应力强度评定。结果表明 ,该容器错边部位的应力是满足应力分析准则的。通过对存在不同错边量的容器进行应力分析 ,探讨了容器的错边容限 ,对含有错边缺陷在役容器是否合乎使用的判断具有一定指导意义     

手持式GPS测量在地球化学勘查中的应用

在大比例尺的化探测量中，用GPS单点绝对定点技术来进行测网的布设，减少了控制测量环节。降低了生产成本。因此，GPS绝对定点在化探测量中仍有应用的前景。但是，绝对定位时必须做到：(1)合理选择校正的控制点(三角点或四角点)；(2)正确校正参数；(3)定期地检测仪器；(4)保证仪器的高度角和有效工作时间。本次该方法应用在化探的测网布设中。实测面积7km^2，经传统测量仪器检查验收，证明文中提出的方案完全可以用于生产实践。     

沾化凹陷南斜坡油气运移条件及运移特征研究

油气运移的条件和油气运移的特征决定了油气藏的形成与分布。沾化凹陷南斜坡不整合面、断层以及各层系储集砂体的空间配置构成复杂的立体网络通道，决定了油气的运移，控制了油气分布。以断层为垂向运移通道的油气藏常在断层带附近多层叠置；以连通砂体为主要运移通道的油气藏常形成于距烃源层较近或相邻的层位；以不整合面作为运移通道往往可使油气长距离运移形成各种地层油气藏。沾化凹陷南斜坡的油气藏都是油气经过两种或多种输导层阶梯式运移而形成的。砂体、断层和不整合面组成的输导系统的末端和边缘是油气运移的重要指向区。     

Frames of Reference in Mobile Augmented Reality Displays.

In 3 experiments, the authors investigated spatial updating in augmented reality environments. Participants learned locations of virtual objects on the physical floor. They were turned to appropriate facing directions while blindfolded before making pointing judgments (e.g., "Imagine you are facing X. Point to Y"). Experiments manipulated the angular difference between the learning heading and the imagined heading and between the actual heading and the imagined heading. The effect of actual-imagined on pointing latency was observed for naive users but not for users with brief training or instructions concerning the fact that objects can move with body movements. The results indicated that naive users used an environment-stabilized reference frame to access information arrays, but with experience and instruction the nature of the representation changed from an environment stabilized to a body stabilized reference frame. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

江苏复杂断块高含水单元改善水驱效果的技术对策

在分析高含水开发单元特点的基础上,针对该阶段剩余油的品位、分布和油水关系极为复杂、挖潜难度大的技术难点,提出了适合江苏复杂断块油田高含水开发单元改善水驱开发效果的思路和工作程序、技术对策,并在真武油田高含水开发单元进行了实际应用,取得了良好的效果.     

陆相断陷湖盆中层序边界的形成机理及其识别特征研究

陆相断陷湖盆中层序边界是由于沉积物表面高出沉积基准面或盆地基准面、沉积物发生剥蚀或无沉积作用所形成的，其产生机理主要有边界断层停止活动、断块翘倾活动、湖盆整体抬升和湖平面下降。层序边界在地震特征上、测井曲线上、钻井剖面中的岩性、岩相特征、古生物组合、微量元素的变化上均有明显的特征。利用这些特征，在济阳坳陷下第三系中识别出9个三级层序。     

GSM技术在配电网故障自动隔离及恢复系统的应用

为了使配电网故障的隔离和恢复的通讯更加可靠、迅速、经济，设计了一种基于GSM通讯技术，借助移动通讯系统短信业务和数据业务，实现配电网故障的自动隔离与恢复的系统。该系统通过MCU采集数据，判断故障位置与故障类型，经GSM通讯模块上传主站，主站统筹全局，实现故障段的切除，非故障区的供电。阐述了系统的工作原理、硬件结构、通讯协议和软件流程。现场的实际运行情况证明数据上报通讯准确率为100％，多次模拟线路故障，根据故障点的不同，一般在2～3min内系统都能可靠的隔离故障，恢复系统。     

一种T形高压输电线路故障测距新方法

对T形线路的故障测距，现有方法都是先判断故障支路，再将3端线路等效成2端线路进行测距。但在 T节点附近短路，尤其是经高阻短路时，现有的测距方法由于无法正确判别故障支路而存在一定范围的测距死区。针对上述缺陷，分别假设故障发生在某一支路，由假定正常的2段支路端的电压、电流推算求得 T节点电压和注入假定故障支路的电流，从而分别求得3个故障距离。经证明，求得的3个故障距离有且仅有1个在0和对应支路总长度之间，该距离就是真实的故障距离，故障发生在对应支路上。该方法无需事先判别故障支路即可测距，在 T节点附近经高阻故障时无测距死区。其测距精度理论上不受过渡电阻和故障类型影响，无需故障前数据，且对滤波无高要求。EMTP仿真结果表明该方法正确、有效，测距精度高。