基于振动声学的电力变压器绕组在线监测及特征参量提取

传统绕组检修方法包括短路阻抗法、频率响应法及低压脉冲法,但仅适用于离线或停电检测,影响变压器正常运行.介绍了基于振动声学的电力变压器绕组在线监测与故障诊断技术,采用加速度传感器检测绕组振动声学信号,结合频域分析法及峰值频率、频率偏移、总谐波畸变率、基频能量比、互相关系数等特征参量实现绕组状态评估.     

短路阻抗法结合频响法诊断变压器绕组变形的分析与应用

由变压器绕组变形直接或间接导致的变压器损坏事故率居高不下,开展变压器绕组变形检测与诊断方法的研究十分必要。诊断变压器绕组变形的方法有低电压脉冲法、频响法和短路阻抗法,本文主要阐述了频响法和短路阻抗法的测试原理,给出了将频响法及短路阻抗法2种方法相结合进行综合应用的实例。结果表明,用短路阻抗法结合频响法诊断变压器绕组变形可有效提高检测结果的正确性和准确性,是一种值得推广的检测变压器绕组变形的方法。     

基于MSOGI的变压器短路阻抗在线辨识方法

变压器等效电路参数与绕组的状态有关,绕组变形是引起变压器内部匝间故障的主要原因,可以通过辨识短路阻抗检测出来。实际中通常采用短路实验来测量这些参数,这是离线检测的方法。提出了一种实时在线监测变压器短路阻抗的新方法,采用并联式二阶广义积分器(MSOGI)提取变压器一、二次电压和电流的基波分量,由微分方程算法在线辨识出变压器的短路阻抗并进行了实验研究,实验结果证明了所提出方法的可行性和有效性。     

变压器绕组变形的扫频短路阻抗法研究

针对变压器因绕组变形而产生故障问题,分析了现有短路阻抗法和频响法检测绕组变形手段的特点和不足,研究了扫频短路阻抗法的基本原理和测试接线方式,在模型变压器上进行了绕组层间短路、绕组匝间短路等不同情况的试验测试,初步验证了该方法的有效性。以某220 kV变压器为测试对象,采用扫频短路阻抗法进行了变电站现场测试工作。该方法测试结果能够提供更多的测量参量,为绕组变形的研判提供了更多的参考依据,是一种很有价值的变压器绕组变形测试方法。     

基于短路阻抗法的变压器绕组变形测试装置开发

变压器在运行中可能发生绕组变形,测试绕组变形的方法主要有频响法和短路阻抗法。频响法对测试人员的专业技术水平要求高,不利于现场普及。文中研制一套基于短路阻抗法的变压器绕组变形测试装置,该装置测试方法简单,易于判断绕组是否发生变形。在常德电业局乾明变电站的测试结果显示,该装置测试准确,为现场变压器绕组变形的测试提供了一种有效手段。     

基于短路阻抗及ΔU-I1轨迹特征联合分析的变压器绕组变形故障在线检测方法

为解决短路阻抗法不能进行故障类型识别及其与ΔU-I1轨迹法均易受设备测量误差干扰的问题,提出了基于短路电抗及ΔU-I1轨迹特征联合分析的绕组变形在线检测方法.介绍了在线短路阻抗法的原理,并根据互感器测量误差的短时不变性提出了减小测量误差的计算方法.介绍了ΔU-I1轨迹法的原理,然后给出基于短路阻抗及ΔU-I1轨迹特征联合分析的变压器绕组变形在线检测步骤和判据.通过建立变压器的仿真模型,对所提方法的有效性及考虑测量误差时的准确性进行了验证.结果表明,所提方法能在考虑测量误差时准确识别变压器的绕组变形故障,具有工频带电监测和故障类型识别的优点,提高了绕组变形故障识别的精度.     

变压器绕组变形测试方法及应用

介绍了频率响应法和短路阻抗法测试变压器绕组变形的基本原理,比较了两种方法测试方法的灵敏性,对一台变压器绕组变形测试结果进行了分析.     

变压器绕组变形的综合诊断分析

电力变压器遭受短路冲击后,应尽快判别绕组损坏情况.利用频响分析法、短路阻抗法、绕组电容量法,结合绝缘油色谱分析、绕组直流电阻测试和电压变比测试等试验对一遭受短路冲击后的变压器绕组变形情况进行综合诊断分析.经验证,综合分析结果与实际情况一致.     

变压器短路阻抗在线监测的场路耦合法仿真及试验

目前变压器短路阻抗在线监测的研究主要基于电路等效的理论推导,所采用电路模型仿真无法模拟变压器发生绕组变形时磁场的变化。为了给变压器短路阻抗在线监测装置的开发提供更加精细的仿真与实际运行数据支持,设计了绕组可轴向活动的单相双绕组油浸式变压器。根据变压器的实际参数对其进行"磁场-电路"耦合法仿真,研究计算变压器正常运行与绕组发生轴向位移情况下短路阻抗的大小,并开展相应的试验对仿真结果进行验证。得到的试验结果与仿真结果一致,表明该仿真方法能够正确仿真变压器在线运行情况;并且结果显示,当绕组发生轴向位移时短路阻抗增加。     

变压器绕组变形在线监测算法的改进

国内外的研究和统计表明,变压器绕组变形是电力系统安全运行的一大隐患,通过测量变压器绕组短路电抗来判断变压器绕组是否变形是一种有效方法。利用在线测量变压器原、次边的电压和电流量,采用递推最小二乘法(RLS)辨识变压器的短路阻抗的方法来进行变压器绕组变形在线监测。通过仿真测试结果表明,该方法能有效监测变压器绕组变形。     

阻抗法和频响法诊断电力变压器绕组变形

简要介绍了阻抗法和频响法测量电力变压器绕组变形的基本原理和实现方法,比较分析了阻抗法和频响法对两种典型变形测试的灵敏性,并指出了两种方法的互补性。在初步总结诊断绕组变形基本规则的基础上,对某次变压器绕组办形故障进行了分析和诊断。     

一种变压器绕组变形综合检测仪器的设计

绕组变形是电力变压器正常运行过程中常见的一种故障隐患。准确诊断电力变压器绕组的变形情况,有助于保障电力系统的安全可靠运行。设计开发了一种兼具频率响应法和低压电抗法两种测量原理的变压器绕组变形综合检测仪器,其不仅可以满足频率响应法和低压电抗法的所有技术要求,而且结构轻便、操作简单,可方便地用于现场电力变压器绕组运行状况的有效检测和综合诊断。     

Field-winding fault detection in synchronous machines with static excitation through frequency response analysis

Frequency Response Analysis is a well-known technique for the diagnosis of power transformers. Currently, this technique is under research for its application in rotary electrical machines. This paper presents significant results on the application of Frequency Response Analysis to fault detection in field winding of synchronous machines with static excitation. First, the influence of the rotor position on the frequency response is evaluated. Secondly, some relevant test results are shown regarding ground fault and inter-turn fault detection in field windings at standstill condition. The influence of the fault resistance value is also taken into account. This paper also studies the applicability of Frequency Response Analysis in fault detection in field windings while rotating. This represents an important feature because some defects only appear with the machine rated speed. Several laboratory test results show the applicability of this fault detection technique in field windings at full speed with no excitation current.     

变压器绕组微小变形脉冲响应检测系统的设计

频率响应法( FRA)广泛应用于变压器绕组变形的检测.针对传统的扫频方式检测频带窄,灵敏度低且测试速度慢的缺点,本文设计了一套基于纳秒脉冲响应法的变压器绕组微小变形检测系统.系统的硬件部分由纳秒脉冲源、高速采集模块、阻抗匹配器和计算机构成.其中纳秒脉冲源可产生上升沿5ns、半脉宽50ns、幅值2kV的双指数脉冲.采用L...     

电力变压器绕组变形故障的测量分析与判断

采用频响分析法（ＦＲＡ）测量电力变压器绕组的变形故障,具有灵敏度高、试验设备轻便、判断直观的优点。但是,频响分析法也受到诸多因素的影响,要求试验人员具有较高的测量分析能力。本文就测量方法和分析判断的一般原则提出了一些可行的原则,并对电力变压器绕组的变形故障的各种测试方法及其应用前景提出了一些建议。     

用机械振动频响法诊断大型变压器绕组松动

开展变压器绕组及铁心监测及诊断方法的研究,及早发现变压器绕组松动,避免突发事故具有十分重要的意义.利用机械振动频响法,通过对变压器的箱壁振动信号的测试和分析,对上海武威变电站220 kV变压器的绕组松动进行了测试分析,提出了诊断变压器绕组松动的新方法.     

The Application of the Digital Computer in the Control Systems Laboratory

Particularly in undergraduate courses in Control Systems, students are introduced to the three main design criteria, Root Locus, Frequency Response, and Transient Response. These methods are normally applied to analysis rather than synthesis or design due to this type of problem having an easier solution and the lack of student time to attempt the latter type of problem. With this problem in mind a number of computer programs were written to remove the main labor of computation involved in these trial-and-error methods of design. Furthermore, graphical output was provided since this gives the student a better picture of what is happening than does a list of figures. Though the programs were written for an IBM 1620, the flow diagrams are applicable to any similar computer having a FORTRAN processor. The graphical plots were programmed for a 407 off-line printer since a plotter was not available.     

New SFRA measurement interpretation methodology for the diagnosis of power transformers

The analysis of the frequency response by the Sweep Frequency Response Analysis method (SFRA) is a diagnosis technique that can detect displacements, deformations and other mechanical and electrical failures in power and distribution transformers. One of the main disadvantages of the method is the lack of an international agreement regarding the methodology for measurement analysis, which is usually done by experts in the field, who normally make the diagnosis with the aid of statistical parameters such as correlation coefficient and standard deviation, or parameters derived from modeling the frequency response as a complex transfer function, represented by poles and zeros, or poles and residues. This paper presents a new methodology for SFRA measurement analysis, which makes use of the properties of various types of parameters and expert knowledge through the application of fuzzy causal diagnosis.     

可控串补晶闸管失控引起的振荡现象机理研究

根据可控串补的时域稳态特性,分析了可控串补在感性调节模式下的两种具体情况,定义了可控串补的正常感性调节模式和深度感性调节模式,分别研究了这两种模式下的振荡现象,指出这些振荡是由于晶闸管失控而产生,并推导了可控串补发生振荡的临界条件。根据不同需求提出了几种电抗值选择原则,对TCSC的规划设计有一定的指导意义。