油浸式电力变压器绝缘受潮故障分析和处理

针对2起变压器故障案例,通过预防性试验测得泄漏电流超标、油色谱试验测得CO、H2、CO2体积比有明显上升趋势,通过试验数据分析,证实是变压器绝缘受潮引起的。分别将2个案例故障类型判断为绝缘局部轻微受潮、油中低能量密度的局部放电。采取了控制变压器本体油位、滤油机的压力（案例1）,对检查中发现的渗漏点进行处理、变压器油中H2进行加热过滤和真空脱气处理（案例2）等一系列措施,预防性试验、油色谱试验数据全部合格。利用气体色谱分析法和电气试验检测法,从不同的角度反映和判断变压器绝缘状况。     

电力变压器绝缘受潮分析及现场处理

电力变压器绝缘受潮是威胁变压器安全稳定运行的重要设备隐患。通过实例对变压器受潮原因进行了分析,论述了电力变压器绝缘受潮诊断方法,并通过实践提出解决变压器绝缘受潮现场最佳处理方法。     

大型变压器绝缘受潮后的现场处理

大型变压器绝缘受潮后的现场处理福建省第二电力建设公司张文钦１９９３年底总山变２期扩建安装１台沈阳变压器厂生产的２２０ｋＶ、１２００００ｋＶＡ变压器。安装后发现其线圈有轻度受潮，铁心与外壳间绝缘电阻只有０．１ＭΩ。经热油循环４天，底部用电炉加热，抽真空...     

一起变压器进水受潮故障分析

本文中作者阐述了一起变压器进水受潮故障的检测、处理及原因分析的过程。通过对变压器内外部水分来源的分析,给出故障产生的原因。同时提出了解决办法,为杜绝以后类似故障的发生提供参考。     

500 kV油浸式电力变压器内部绝缘击穿故障分析

分析一起500 kV油浸式电力变压器内部绝缘击穿故障.通过对故障变压器的油箱、高压套管及内部进行检查,并结合故障录波图进行分析,确定了放电主通道、放电诱发原因以及故障发生过程,认为变压器高压套管下均压球和铁轭之间油隙击穿是导致变压器发生爆炸的主要原因.根据故障原因制定了同类故障的防范措施,建议对采用类似设计的变压器进行整改.     

110kV油浸式电力变压器绝缘受潮故障原因分析及处理

对一起110kV油浸式电力变压器绝缘受潮故障的原因进行了分析,并叙述了变压器干燥处理过程。     

安装阶段防止大型变压器绝缘受潮的措施

针对大型电力变压器在安装阶段出现的绝缘受潮问题,介绍变压器绝缘受潮的物理过程,提出了有效防止绝缘受潮的方法。     

利用变压器中的油纸水分平衡关系分析绝缘受潮

利用油—纸绝缘系统含水量平衡曲线，分析了运行中变压器油——纸绝缘结构的水分平衡特性，并通过实例对变压器绝缘受潮的原因进行了分析。     

220kV电力变压器局部受潮问题的现场处理

某变电站220 kV电力变压器正常运行时遭受雷击后起火,灭火过程中消防水进入变压器,致变压器局部受潮。现场通过绕组短路的方法将变压器绝缘油温度维持在约80℃,利用变压器纸—油绝缘水分动态平衡特性,通过真空滤油机持续滤除绝缘油中的水分,使变压器器身绝缘水平恢复至正常,干燥后的变压器投入运行,色谱测试结果正常,运行状况良好。     

一种基于MIA的油浸式变压器放电性故障定位新方法

为解决油浸式电力变压器中低能放电、高能放电等放电性故障的定位问题,提出了基于油中金属分析(Metal In-Oil Analysis,MIA)的放电性故障定位方法。通过对变压器内部高故障概率构件进行表面处理,将潜在的故障信息源预置于构件表面,并应用示位金属(Metal for Position Indication,MPI)进行发生故障构件的确定。在此基础上,结合已有的局部放电、油中溶解气体分析等在线监测系统进行软、硬件的整合,可以实现较为完善的变压器放电性故障的诊断与定位。研究结果表明,该方法在提高放电性故障定位精度的同时,还可以降低对原有某种特定故障定位方法在精度方面的要求,并通过连续监测使运行维护人员对变压器的潜伏性故障信息有更为全面的掌握,为变压器状态检修的实现提供了新的技术支撑。     

On the estimation of elapsed life of oil-immersed power transformers

Inadvertent failure of power transformers has serious consequences on the system reliability, economics, and the revenue accrual. An accurate estimation of transformer life can, to a very large extent, mitigate the problems, besides satisfying the conflicting requirements of optimum utilization of the equipment and safeguarding the reliability. In this endeavour, the authors have planned long duration aging experiments on scaled-down (prorated) models of a transformer, incorporating all of the essential features of actual equipment under normal operating electric stress and accelerated thermal stress. In continuation of the authors' earlier experimental investigations, an elapsed life assessment study has been instituted by acquiring insulation-aging data under accelerated thermal stresses.     

几台变压器的故障分析与处理

介绍由于35kV系统经常性的线路短路所引发的变压器中低压线圈变形失稳这一潜伏性故障的发生、发展过程中的检测、分析判断及故障处理的过程及超声波局放信号检测定位的实际应用。概述由于变压器生产厂家生产工艺管理控制不严，在铁心叠装中出角处绝缘纸板插错导致运行中色谱分析总烃异常升高这一复杂的故障分析处理过程，以及由于设计时考虑不周，主变压器高压出线绝缘不足酿成主变压器差动保护动作的故障分析处理过程，对3种不同类型故障机理进行理论分析，提出变压器全过程的具体措施。     

代价敏感相关向量机的研究及其在变压器故障诊断中的应用

实际中不同变压器故障类型的误分引发的危害程度往往不同,仅追求正确率并不一定会带来符合实际意义的分类结果。针对此,提出了代价敏感相关向量机(CS-RVM)。CS-RVM以误分代价最小为目标,按贝叶斯风险理论预测新样本类别。在用典型算例验证了CS-RVM具有代价敏感性的基础上,尝试将其应用于变压器故障诊断。基于溶解气体分析(DGA)数据的变压器故障诊断实例分析表明,CS-RVM全局诊断正确率略高于BP神经网络和支持向量机,略低于多分类相关向量机(M-RVM),但CS-RVM趋于提高误诊代价高的故障类型的诊断正确率,具有代价敏感性;CS-RVM的诊断速度足以满足变压器故障诊断的工程要求。     

油浸变压器常见事故的处理及预防措施

变压器漏油和起火是油浸变压器在运行过程中的常见问题,为此,针对变压器结构设计不合理、制造工艺水平不高、材质选用不当及现场安装操作不规范等几方面因素提出相应的处理方法及预防措施,以解决变压器渗漏油及防火问题,保证电网的安全稳定运行。     

电力变压器直流电阻异常的实例分析

通过三个直流电阻异常的实例,综合油色谱和其他电气试验对故障进行了分析诊断,在此基础上总结了电力变压器直流电阻异常的故障诊断思路和方法。     

10 kV油变和箱变战略采购LCC研究与应用

针对上海市电力公司战略采购设备10kV油变和箱变,利用全寿命周期成本(LCC)方法,结合抽检试验得到的相关技术评价情况开展了研究和实际评标工作.根据10kV油变和箱变设备在全寿命周期的运行特点,估算各设备在全寿命周期所耗费的费用,在经济评估中结合技术指标,充分发挥战略采购优势,以使企业更为合理地进行采购及设备管理,降低企业的成本,并有效节约社会资源.     

Diagnosis of oil-immersed transformers by colorimetry of insulating paper

Power transformers have been expected to work with safety and reliability over a period of more than 30 years. The life expectancy of transformers depends upon the degree of deterioration of insulating materials, particularly conductor insulating paper. Many attempts have been made in recent years to estimate the degree of deterioration of transformers but no diagnostic techniques have been put into practical use because of the difficulty of taking into account the service conditions. It is well known that materials change color when they deteriorate, but no colorimetry study has been made on material deteriorations. According to the recent advances in instrumentation and data processing equipment, the color of materials has become easy to measure qualitatively. Therefore, the basic investigation on colorimetry of insulating papers has been made to clarify the applicability to power transformers. Test results showed a strong correlation between the color difference and the deterioration of insulating paper. This report discusses the effect of materials of papers and impregnating oils on colorimetry.     

A neural network-based scheme for fault diagnosis of power transformers

This research presents an artificial neural network (ANN)-based scheme for fault diagnosis of power transformers. The scheme is designed to detect the fault, estimate the faulted side, classify the fault type and identify the faulted phase.The proposed fault diagnosis scheme (FDS) consists of three hierarchical levels. In the first level, a pre-processing of input data is performed. In the second level, there is an ANN which is designed to detect the fault and determine the faulted side if any. In the third level, there are two sides diagnosis systems. Each system is dedicated to one side and consists of one ANN in series with four paralleled ANNs (for fault type classification).The proposed FDS is trained and tested using local measurements of three-phase primary voltage and primary and secondary currents. These samples are generated using EMTP simulation of the High Dam 15.75/500 kV transformer substation in Upper Egypt. All the possible fault types were simulated. The fault locations and fault incipience time were varied within each fault type. Testing results proved that the performance of the proposed ANN-based FDS is satisfactory.     

Internal fault current identification based on wavelet transform in power transformers

This paper presents a novel approach for differential protection of power transformers. This method uses wavelet transform (WT) and adaptive network-based fuzzy inference system (ANFIS) to discriminate internal faults from inrush currents. The proposed method has been designed based on the differences between amplitudes of wavelet transform coefficients in a specific frequency band generated by faults and inrush currents. The performance of this algorithm is demonstrated by simulation of different faults and switching conditions on a power transformer using PSCAD/EMTDC software. Also the proposed algorithm is tested off-line using data collected from a prototype laboratory three-phase power transformer. The test results show that the new algorithm is very quick and accurate.