漫湾发电厂3号主变A相故障的气相色谱分析

利用气相色谱分析方法,就漫湾发电厂3号主变A相目前存在的故障原因进行了分析判断,简述了变压器过热性故障判断的依据,并通过对主变放油内检得到了验证.     

漫湾发电帮3号主变A相故障的气相色谱分析

利用气相色谱分析方法，就漫湾发电厂3号主变A相目前存在的故障原因进行了分析判断，阐述了变压器过热性故障判断的依据，并通过对主变放油内检得到了验证。     

油浸式变压器铁芯多点接地故障诊断与处理

万家寨水电站2号主变压器运行至2015年,在进行第一季度、第二季度油中溶解气体色谱分析时,发现变压器内部存在高温过热故障,对铁芯进行绝缘电阻测量,阻值为0Ω。本文通过对万家寨水电站220kV大型油浸式变压器铁芯多点接地故障的处理,阐述了如何运用变压器油中溶解气体色谱分析、电气性能试验等方法,进行故障诊断和识别,并介绍设备故障的处理方法,供参考。     

变压器油再生处理实践探讨

对某电厂500 kV主变、18 kV SFC系统变压器的不同的故障情况进行了简要介绍,并对相应的油再生处理工作进行了探讨。     

35 kV桃崇线电缆故障分析

2014年6月500 kV崇左变电站发生了一起35 kV站用电源线电缆终端端子熔解断落故障,通过对故障点情况的分析,得出故障的主要原因是由于雷击35 kV桃崇线2号杆C相造成线路三相短路,较大的工频短路电流较长时间地流过接触不良的电缆终端端子导致电缆锥头过热后烧坏熔断.笔者通过对电缆头熔解断落情况进行分析,提出了防止此类故障发生的措施和建议.     

主变低压侧封闭母线接头过热分析及处置

以某电厂1号主变低压侧封闭母线接头过热故障为例,分析过热原因及叙述处理过程,给电厂检修维护人员提供参考,防止类似事件发生,保障设备安全供电.     

一大型水电站在双向潮流约束条件下的AGC功能策略设计

主要针对国内一大型水电站AGC成组运行有功策略分配原则、220 kV系统与500 kV系统联络变4号主变压器不能过载运行,将4号主变功率纳入3号机可调范围计算策略以及对多台机组成组下其组合振动区模型建立的方法进行了阐释,并对AGC投入的安全策略进行了分析。为其他电站AGC策略设计提供相关参考。     

桐柏电站发电机开关油泵报警分析及处理

机组开关作为发电电动机组并网的同期点和500 kV主变的明显电气断开点,其性能状态直接影响到电站设施运行安全性和稳定性。桐柏电站1号机组抽水调相工况转换到抽水工况过程中,上位机报1号发动机开关油泵运行时间长报警,本文对此故障信号进行了详细的分析并寻找解决办法。     

500 kV变压器典型雷击故障分析及对策

分析2009年8月22日百色变电站S1号主变C相雷击故障.结合后期试验收集的数据信息以及解体、仿真等信息对C相变压器本体故障原因进行深入分析,最终发现故障是由于主变220 kV侧直击雷防雷设计存在盲区导致雷击主变,同时根据本次事故提出改进措施,为同类工程提供参考借鉴.     

单相CT极性反接对主变差动电流的影响

巴基斯坦某水电站5号机组开机并网后,在增负荷过程中220 kV主变C相差动保护动作,根据主变保护装置故障录波及报文数据,发现事故原因为主变低压侧B相CT绕组极性反接,调整其极性后再次开机,机组、主变正常投运,故障解除。在此故障现象的基础上,分析了YNd11联接组别的变压器,在不同的差动保护相位调整方式下,主变高、低压侧单相CT二次绕组极性反接时,对保护装置三相差动电流计算的影响。     

基于因子分析法的滑坡变形分析

滑坡位移监测资料是我们认识滑坡的基本信息之一,但并非任何的滑坡监测资料都能够直观地反映出滑坡的变形特征,因此采用因子分析法对三峡库区某滑坡的位移监测资料进行分析,将滑坡监测点作为变量,找出了能够反映监测资料原始数据的3个公共因子,并求得了各公共因子的载荷矩阵。此外,根据因子载荷的分布及其监测点变量反映的信息确定了各公共因子的实际意义,得知库水是影响滑坡变形的主要因素,降雨次之,监测点所在微地貌形态对变形也具有一定的影响。同时,由因子载荷求出了库水因子作用下的位移量,并通过滑坡主剖面上中前部监测点的累积位移变化趋势,对该滑坡在库水作用下的变形机理进行了分析。     

对河口水库“99630”梅雨洪水分折

1999年6月，湖州地区遭遇了百年未遇的特大洪灾。据湖州市40处雨量站资料分析，其7d、15d、30d最大降雨均接近或超过200年一遇，给湖州市的工农业生产和人民生命财产造成了巨大损失。位于德清县境内的对河口水库亦发生了建库以来的最大洪水，水库出现了险情，造成了一定损失。现从水文资料整编的角度对此次洪水进行初步分析。     

EMS中静态安全分析模块实用化分析

本文介绍安全分析的分类和概况,简要概述几种主流的静态安全分析开断故障算法,继而针对电网实用化中的几个关键问题进行详细阐述,最后对该领域进行总结和展望.     

基于因子分析法的白水河滑坡影响因素分析

滑坡位移受众多因素影响,找出主要影响因素对于认识滑坡诱发机理、演化过程具有重要意义。以白水河滑坡为研究对象,依据2009—2011年位移监测资料,选取当月降雨量、前两月降雨量、当月库水位最高值、当月库水位平均值等4个影响因素作为变量进行因子分析,得到了反映白水河滑坡位移与外界诱因的两个主要因子和因子载荷矩阵,进而按年度分析了影响白水河滑坡位移的主要因素。综合分析4个影响因素在因子Ⅰ上的载荷量,得出各因素对白水河滑坡位移影响从大到小顺序为前两月降雨量当月降雨量月库水位最高值月库水位平均值。     

Rapid Sediment Assessment: Indicator Analysis and Screening Analysis Approaches

Efficiently characterizing the distribution of contaminated and toxic sediments in rivers and harbors is usually limited by the expense of conventional chemical and toxicological analyses. Two approaches were developed to address this problem; the indicator analysis approach, used in the ARCS project, and the screening analysis approach, here applied to a sediment assessment project on the Ottawa River (Toledo, Ohio). The indicator analysis approach utilized two suites of analyses; 23 conventional toxicological and chemical analyses performed on a subset of samples, and 11 rapid, inexpensive chemical and toxicological assays performed on many samples, including those analyzed using the conventional analyses. Predictive correlation equations were generated using step-wise linear regression, and these equations were used to calculate values for the conventional analyses for samples on which they were not performed. This approach generated statistically strong predictive equations, as well as a “weight of evidence” data set useful for evaluating relative sediment contamination. The equations, however, were very site-specific, and sometimes contained terms which were counter-intuitive, and the approach failed if the data sets contained too many “non-detect” or 100% mortality values. The screening analysis approach measured total PCBs by enzyme immunoassay (EIA) and 18 elements by x-ray fluorescence spectroscopy (XRF). These analyses correlated very strongly with gas chromatography (GC) and atomic absorption spectroscopy (AA), respectively, and their production rates and costs were far superior. A low bias was observed in the EIA data, compared to the GC data, possibly due to inefficient EIA extraction of the oily sediments, or to a mismatch between the PCB mixtures in the sediment and used as a calibrator for the EIA. XRF data for Cr, Cu, Mn, Ni, Sb, and Zn exhibited a positive bias compared to AA, while Cd and Pb did not. This was probably due to metal-specific variations in the contribution of mineral matrix-associated metal to the acid-digestible metal quantified by AA. Both EIA and XRF can be performed in the field, to produce near-real time data to guide sampling. Detection limits of the PCB EIA (0.12 μg/g DW) and of XRF (typically 5 to 15 μg/g DW) are adequate for most sediment assessment projects. Of the two approaches, screening analyses are recommended for the rapid, cost-effective characterization of contaminated sediments.     

Regional Dry Spells Frequency Analysis by L-Moment and Multivariate Analysis

The spatial variation of the statistical characteristics of the extreme dry events, such as the annual maximum dry spell length (AMDSL), is a key practice for regional drought analysis and mitigation management. For arid and semi arid regions, where the data set is short and insufficient, the regionalization methods are applied to transfer at-site data to a region. The spatial variation and regional frequency distribution of annual maximum dry spell length for Isfahan Province, located in the semi arid region of Iran, was investigated using a daily database compiled from 31 rain gauges and both L-moment and multivariate analysis. The use of L-moment method showed a homogeneous region over entire province with generalized logistic distribution (GLOG) as the regional frequency distribution. However, the cluster analysis performed two regions in west and east of the province where L-moment method demonstrated the homogeneity of the regions and GLOG and Pearson Type III (PIII) distributions as regional frequency distributions for each region, respectively. The principal component analysis was applied on at-site statistics of AMDSL and found the L-coefficient of skewness (LCs) and maximum AMDSL the main variables describing the spatial variation of AMDSL over the Isfahan Province. The comparison of two homogeneous regions also proved the difference between two regions. Therefore, this study indicates the advantage of the use of multivariate methods with L-moment method for hydrologic regionalization and spatial variation of drought statistical characteristics.     

浅谈条分法理论的缺陷

在岩土工程中计算边坡稳定性和土钉墙设计，都可以使用条分法进行计算。但在众多土钉墙的事故后面，除了对施工环节的反省之外，很少有人怀疑过条分法理论的正确性。本文主要讨论条分法在数学和力学理论上的不严谨性及其对工程的危害。     

万家寨引黄工程总干线一、二级泵站防火喷涂项目索赔分析

万家寨引黄工程总干线一、二线泵站防火喷涂项目，在施工过程中，承包商提出了索赔要求，本文介绍了该项目索赔的分析过程，包括索赔证据的确立及索赔费用计算等。     

基于三维数值分析的土钉支护结构研究

以某土钉支护形式的基坑工程为依托,结合土体和土钉的复合作用机理,建立土钉支护结构的 三维数值模型。采用Ｍｏｈｒ－Ｃｏｕｌｏｍｂ塑性模型,对基坑分步施工的过程进行了模拟分析,得出土钉拉力、 坡顶水平位移和地面沉降的发展规律。研究结果表明:数值计算得到的基坑坡顶土体水平位移、竖向沉 降的结果与现场监测数据基本吻合,整体三维模拟结果更接近实测值;土钉的拉力与长度、所处开挖面 位置有相关性,拉力最大值随开挖深度的大小而发生变化。