基于油中溶解气体的变压器内部故障分析

变压器油中溶解气体分析技术,是用气相色谱分析变压器油样中溶解气体的成分和含量,判定变压器有无内部故障,诊断故障类型,并推定故障点的温度、故障能量等。介绍了变压器故障时产气特征,分析了基于三比值法的变压器故障类型判断方法,并结合三个实际案例分析了此方法的故障诊断效果。     

支持向量机在电力变压器故障诊断中的应用

利用支持向量机的学习方法，构建了电力变压器故障诊断模型，该模型将变压器故障分为放电性和过热性两大类，通过统计分析寻求特征量区分类间的故障类型，采用支持向量机识别类内的故障类型，利用基于交叉验证的网格搜索法来确定支持向量机的参数．考虑到变压器油中溶解气体特征空间的紧致性原理，利用模糊C均值聚类算法对所获取的样本进行预选取，有效解决了确定模型参数耗时巨大的问题，并在一定程度上提高了模型的推广能力．实例验证表明，该模型在有限样本情况下，能达到较高的变压器故障判断率，放电性故障样本正确判断率为90．5%，过热性故障样本正确判断率为85．9%，说明该模型具有很好的分类效果和推广能力．     

样本规范化在故障诊断神经网络方法中的应用

在神经网络模型中,训练样本的不同特征变量(输入变量)反映响应变量(输出变量)的灵敏程度有一定的差别,若将各特征变量直接作为神经网络的输入,则会湮没一些弱小量可能含有的有效信息.采用油中溶解气体分析法建立以变压器油中溶解气体含量为输入,变压器故障类型为输出的BP神经网络变压器故障诊断模型,分别运用最大值最小值规范化、一般浓度规范化、特征浓度规范化三种方法对训练样本进行规范化.研究结果表明,不同样本规范化方法对故障诊断效果的影响显著,运用特征浓度规范化进行规范化处理要优于其他方法.     

基于油中溶解气体分析的变压器绝缘故障模糊诊断及应用

变压器绝缘故障诊断问题是电力系统维护中的关键问题,常用的故障诊断方法一般是基于油中溶解气体分析法的。重点介绍了基于油中溶解气体分析的一种新方法,即变压器绝缘故障模糊诊断法,在分析一般故障诊断方法优缺点的基础上,根据实例验证了将模糊诊断法应用于电力变压器绝缘故障诊断的可行性。     

浅谈变压器油色谱在线监测系统

对于油浸式电力设备,尤其是变压器,油中溶解气体进行在线或者离线的气体含量分析技术是一种可靠有效的诊断设备潜伏性故障的检测技术,可以判断设备内部的隐藏缺陷,目前它在变压器的预防性监测中其重要性列于首位。变压器油中溶解气体在线监测装置的出现弥补了常规油色谱分析的不足,实现了在线智能化监测与故障诊断,可以及时掌握变压器的运行状况,发现和跟踪潜伏性故障。本文就变压器油色谱在线监测的应用必要性、意义、理论及实际依据、设计进行简单分析。     

支持向量机在电力变压器故障诊断中的应用

利用支持向量机的学习方法，构建了电力变压器故障诊断模型．该模型将变压器故障分为放电性和过热性两大类，通过统计分析寻求特征量区分类间的故障类型，采用支持向量机识别类内的故障类型，利用基于交叉验证的网格搜索法来确定支持向量机的参数．考虑到变压器油中溶解气体特征空间的紧致性原理，利用模糊C均值聚类算法对所获取的样本进行预选取，有效地解决了确定模型参数时耗时巨大的问题，并一定程度提高了模型的推广能力．实例验证表明，该模型在有限样本情况下，能达到较高的变压器故障判断率，放电性故障样本正确判断率为90．5％，过热性故障样本正确判断率为85．9％，说明该模型具有很好的分类效果和推广能力．     

基于油中溶解气体在线监测的变压器故障动态预警方法分析

目前,我国110kV及以上等级的大型电力变压器主要采用油纸绝缘结构,变压器油同时承担着绝缘介质和冷却媒质的作用,是油浸式变压器的重要组成部分.变压器油中包含70％的变压器故障信息,对油中溶解气体进行色谱分析是常用有效的一种变压器故障诊断方法.通过总结利用变压器油中溶解气体进行故障诊断的两大类经典方法,在此基础上分析并提...     

基于BP神经网络的变压器故障诊断方法

本文利用BP神经网络对变压器进行故障诊断。该方法以变压器油中特征气体的含量作为输入参数,输入到经过训练之后的BP神经网络,经过实际输出与期望的对比分析表明,采用该方法对变压器进行故障诊断是有效的。     

通过气相色谱分析变压器的潜伏性故障

利用气相色谱法预测变压器的潜伏性故障是通过定性、定量分析溶于变压器油中的气体来实现的。由于故障气体的组成和含量与故障的类型和故障的严重性有密切关系,所以定期分析溶解于变压器油中的气体就能及早发现变压器内部存在的潜伏性故障,并随时掌握故障的发展程度。通过一些成熟的分析方法,就能够充分掌握变压器的运行状态,提早发现变压器内部故障并给与准确的故障诊断,防止重大事故的发生。     

变压器油色谱在线监测系统的应用和现状

变压器油色谱在线监测系统的应用,能有效地检测出溶解于变压器油中的气体,根据特征气体的组分含量,可以尽早发现变压器的潜伏性故障并可随时监视故障的发展情况。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to