油浸式电力变压器振动与传递特性研究
发布时间：2018-12-13 03:55
【摘要】：随着我国电网电压等级的不断提升和输电容量的不断增加,实际运行中的变压器不可避免地会受到更多不同程度的短路冲击,极易引起铁心叠片松动、绕组形变或预紧力松弛等,这将导致变压器的绝缘和机械性能下降,进而使变压器发生故障。在线振动分析法能够实时监测变压器内部部件的运行状态,但缺乏对采集数据进行合理分析的理论判据,诊断判据尚不完善。为此,本文以一台型号为S11-M-500/35,联结组别为Yyno的油浸式电力变压器为研究对象,通过理论计算、数值仿真、试验分析和故障模拟等手段对变压器振动及其振动能量传递过程进行了深入研究。本文的研究工作对于变压器故障诊断过程中测点位置选择、故障类型判断具有重要的指导意义。结合目前国内外对于变压器振动特性研究已取得的成果,论文首先概括了变压器振动特性以及采用振动法检测变压器状态的国内外研究现状,分析了目前振动法在检测变压器健康状态时存在的主要困难,明确了采用振动法检测变压器状态仍需努力方向和本文开展的主要工作。变压器是一种依据电磁感应定律工作的静止电器。本文利用有限元分析软件,通过电磁固耦合计算,研究了空、负载条件下变压器绕组和铁心磁场分布情况,计算了负载电流条件下变压器的振动特征。结果表明:负载电流条件下变压器的振动特征以100Hz为主,变压器的固体连接杆件在振动能量传递过程只起到衰减变压器振动能量大小的作用,对振动信号频率分布特性的影响较弱。通过搭建负载电流试验平台和振动信号采集系统,试验研究并确定了适宜的测点位置,分析了正常状态下绕组振动的时频特性,验证了仿真模型的准确性。研究结果表明:不同位置处绕组各测点的振动信号主要集中在100Hz,并含有200Hz-500Hz谐波分量,而且振动幅值很小,600Hz以上基本衰减为零,但1/6位置在300Hz处有较明显的谐波分量。结合试验结果并考虑实际监测的方便性,本文认为变压器箱壁距地1/6位置处为适宜的测点位置。设置不同绕组故障来模拟绕组松动、变形等情况,试验研究模拟故障状态下变压器箱壁不同测点的振动情况,对比分析绕组故障前后不同负载电流条件下的箱壁1/6测点处的振动加速度、频域特性等变化情况。结果表明:绕组故障时其振动幅值(基频)与电流之间的线性增大关系并不改变,但故障绕组基频幅值均大于正常绕组基频振动幅值。
[Abstract]:With the continuous improvement of power grid voltage grade and the increasing of transmission capacity in China, transformer in operation will inevitably suffer more and more short-circuit impact, which can easily lead to loosening of the core lamination. The deformation of winding or relaxation of pretightening force will lead to the deterioration of insulation and mechanical properties of transformers, which will cause the transformer to break down. On-line vibration analysis method can monitor the running state of transformer's internal components in real time, but it lacks the theoretical criterion for reasonable analysis of collected data, and the diagnostic criterion is not perfect. Therefore, a oil-immersed power transformer with S11-M-500 / 35 model and Yyno connection group is taken as the research object. Through theoretical calculation and numerical simulation, The transformer vibration and its vibration energy transfer process are studied by means of test analysis and fault simulation. The research work in this paper is of great significance for the location selection and fault type judgement of transformer fault diagnosis. Combined with the achievements of the research on transformer vibration characteristics at home and abroad, the paper first summarizes the vibration characteristics of transformers and the research status quo of transformer state detection by vibration method at home and abroad. This paper analyzes on the main difficulties existing in the vibration method in detecting the healthy state of the transformer at present, and clarifies the direction of the effort still needed to use the vibration method to detect the condition of the transformer and the main work to be carried out in this paper. Transformer is a kind of static electrical apparatus which works according to the law of electromagnetic induction. In this paper, the magnetic field distribution of transformer windings and cores under the condition of empty load and load is studied by using finite element analysis software, and the vibration characteristics of transformer under load current are calculated. The results show that 100Hz is the main characteristic of transformer vibration under load current, and the solid connecting member of transformer can only attenuate the vibration energy of transformer in the process of vibration energy transfer. The effect on the frequency distribution of vibration signal is weak. Through setting up the load current test platform and vibration signal collecting system, the suitable measuring point position is studied and determined, the time-frequency characteristic of winding vibration under normal condition is analyzed, and the accuracy of simulation model is verified. The results show that the vibration signals of the windings at different positions are mainly concentrated at 100Hz and contain 200Hz-500Hz harmonic components, and the amplitude of vibration is very small, and the attenuation above 600Hz is basically zero. But 1 / 6 position has obvious harmonic component at 300Hz. Combined with the test results and considering the convenience of practical monitoring, it is considered in this paper that the location of the transformer box wall at 1 / 6 of the ground distance is an appropriate measuring point. Different winding faults are set up to simulate the loosening and deformation of the winding, and the vibration of different measuring points of the transformer box wall under the simulated fault condition is studied experimentally. The vibration acceleration and frequency domain characteristics of the 1 / 6 measuring point of the box wall under different load current conditions before and after the winding fault are compared and analyzed. The results show that the linear relationship between the amplitude of vibration (fundamental frequency) and the current does not change, but the amplitude of the fundamental frequency of the fault winding is larger than that of the normal winding.
【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM411
[Abstract]:With the continuous improvement of power grid voltage grade and the increasing of transmission capacity in China, transformer in operation will inevitably suffer more and more short-circuit impact, which can easily lead to loosening of the core lamination. The deformation of winding or relaxation of pretightening force will lead to the deterioration of insulation and mechanical properties of transformers, which will cause the transformer to break down. On-line vibration analysis method can monitor the running state of transformer's internal components in real time, but it lacks the theoretical criterion for reasonable analysis of collected data, and the diagnostic criterion is not perfect. Therefore, a oil-immersed power transformer with S11-M-500 / 35 model and Yyno connection group is taken as the research object. Through theoretical calculation and numerical simulation, The transformer vibration and its vibration energy transfer process are studied by means of test analysis and fault simulation. The research work in this paper is of great significance for the location selection and fault type judgement of transformer fault diagnosis. Combined with the achievements of the research on transformer vibration characteristics at home and abroad, the paper first summarizes the vibration characteristics of transformers and the research status quo of transformer state detection by vibration method at home and abroad. This paper analyzes on the main difficulties existing in the vibration method in detecting the healthy state of the transformer at present, and clarifies the direction of the effort still needed to use the vibration method to detect the condition of the transformer and the main work to be carried out in this paper. Transformer is a kind of static electrical apparatus which works according to the law of electromagnetic induction. In this paper, the magnetic field distribution of transformer windings and cores under the condition of empty load and load is studied by using finite element analysis software, and the vibration characteristics of transformer under load current are calculated. The results show that 100Hz is the main characteristic of transformer vibration under load current, and the solid connecting member of transformer can only attenuate the vibration energy of transformer in the process of vibration energy transfer. The effect on the frequency distribution of vibration signal is weak. Through setting up the load current test platform and vibration signal collecting system, the suitable measuring point position is studied and determined, the time-frequency characteristic of winding vibration under normal condition is analyzed, and the accuracy of simulation model is verified. The results show that the vibration signals of the windings at different positions are mainly concentrated at 100Hz and contain 200Hz-500Hz harmonic components, and the amplitude of vibration is very small, and the attenuation above 600Hz is basically zero. But 1 / 6 position has obvious harmonic component at 300Hz. Combined with the test results and considering the convenience of practical monitoring, it is considered in this paper that the location of the transformer box wall at 1 / 6 of the ground distance is an appropriate measuring point. Different winding faults are set up to simulate the loosening and deformation of the winding, and the vibration of different measuring points of the transformer box wall under the simulated fault condition is studied experimentally. The vibration acceleration and frequency domain characteristics of the 1 / 6 measuring point of the box wall under different load current conditions before and after the winding fault are compared and analyzed. The results show that the linear relationship between the amplitude of vibration (fundamental frequency) and the current does not change, but the amplitude of the fundamental frequency of the fault winding is larger than that of the normal winding.
【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM411
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