电力变压器绕组松动变形与振动信号相关研究

发布时间：2018-06-12 08:02

本文选题：电力变压器 + 绕组松动变形　；参考：《昆明理工大学》2017年硕士论文

【摘要】：电力变压器是电力系统中的重要设备,绕组松动变形是变压器故障中最为常见的故障类型之一。电力变压器绕组松动变形故障不能及时发现,电力变压器绕组的机械稳定性将受到很大影响,可能会造成严重安全事故。如何及时有效地检测出电力变压器绕组松动变形故障,对保障电力变压器安全稳定运行具有重要意义。本文从电力变压器绕组机械结构稳定性的角度出发对其进行绕组故障检测,当绕组发生松动变形故障时其机械结构也会发生相应变化,此时电力变压器绕组的模态参数与正常情况相比同样会产生相应改变,模态参数的变化可通过电力变压器绕组振动信号的频响函数进行检测。模态参数随着结构体的改变而发生相应变化,因此可通过对绕组参数的检测与分析实现电力变压器绕组故障检测。首先,对电力变压器绕组常见变形故障及其产生原因进行了简要分析,在此基础上总结了振动分析法在电力变压器绕组变形故障检检测中的应用,同时对模态分析理论进行简介,进一步明确了利用振动频响法对模态参数进行获取可在电力变压器绕组松动变形故障检测中进行应用。其次,进行了电力变压器绕组的数值模态分析即对电力变压器绕组进行有限元建模,分别建立了电力变压器绕组正常工况以及松动变形故障下的前四阶模态振型。通过仿真模型,初步对电力变压器绕组正常状态以及松动故障状态下的模态参数中固有频率的变化趋势进行了掌握。为进一步了解电力变压器绕组松动故障的模态特性,在以50%Fn预紧力作为电力变压器绕组松动故障设置的基础上开展了不同松动程度下的电力变压器绕组固有频率变化研究,通过预紧力的改变发现高阶模态下的变压器绕组松动故障更为敏感,其固有频率变化率更大。再次,为与前述有限元仿真研究相对应,搭建现场实体变压器的绕组试验模态研究平台,分别对变压器绕组正常与50%Fn预紧力松动故障变形时进行模态测试,获取了相应的振动频响曲线。最后从振动频响曲线中提取绕组模态参数,以便通过模态参数的变化对电力变压器绕组进行故障诊断,提出了相应的模态参数提取算法。在上述研究的基础上分别对电力变压器绕组正常与松动故障时的仿真与实验结果进行对比,通过仿真与试验二者固有频率的对比不仅验证了 ANSYS仿真结果,同时明确了电力变压器绕组松动变形时振动频响信号的变化规律,为后续开发基于绕组振动频响信号的电力变压器绕组故障检测系统奠定了基础。
[Abstract]:Power transformer is an important equipment in power system. Loosening deformation of winding is one of the most common types of transformer faults. The loosening and deformation fault of power transformer windings can not be found in time, and the mechanical stability of power transformer windings will be greatly affected, which may cause serious safety accidents. How to detect the loosening deformation fault of power transformer winding in time and effectively is of great significance to ensure the safe and stable operation of power transformer. From the point of view of the mechanical structure stability of power transformer windings, this paper detects the winding faults, and the mechanical structure changes when the winding loosens and deforms. At this time the modal parameters of power transformer windings will also change in comparison with the normal conditions. The changes of modal parameters can be detected by the frequency response function of the vibration signals of power transformer windings. The modal parameters change with the change of the structure, so the fault detection of power transformer windings can be realized by detecting and analyzing the winding parameters. Firstly, the common deformation faults of power transformer windings and their causes are briefly analyzed, and the application of vibration analysis method in fault detection of power transformer windings is summarized. At the same time, the theory of modal analysis is briefly introduced, and the application of vibration frequency response method to obtain modal parameters can be used in the fault detection of loosening deformation of power transformer windings. Secondly, the numerical modal analysis of power transformer windings is carried out, that is, the finite element modeling of power transformer windings is carried out, and the first four modes of power transformer windings under normal working conditions and loose deformation faults are established respectively. Based on the simulation model, the variation trend of natural frequency in the modal parameters of power transformer windings under normal state and loose fault state is preliminarily grasped. In order to further understand the modal characteristics of power transformer winding loosening fault, the natural frequency change of power transformer winding with different loosening degree is studied on the basis of 50Fn pretightening force as the setting of power transformer winding loosening fault. It is found that the loosening fault of transformer windings is more sensitive and the change rate of natural frequency is larger. Thirdly, in order to correspond to the above-mentioned finite element simulation study, the experimental modal research platform of the field solid transformer winding is built, and the modal tests are carried out respectively when the transformer winding is normal and the 50Fn pretightening force loosening failure is deformed. The corresponding vibration frequency response curves are obtained. Finally, the modal parameters of the winding are extracted from the vibration frequency response curve in order to diagnose the fault of the power transformer windings through the variation of the modal parameters, and the corresponding modal parameters extraction algorithm is proposed. On the basis of the above research, the simulation and experiment results of power transformer windings under normal and loose faults are compared, and the results of ANSYS simulation are not only verified by the comparison of natural frequencies between simulation and test. At the same time, the variation rule of vibration frequency response signal when winding loosening and deformation of power transformer is defined, which lays a foundation for the subsequent development of power transformer winding fault detection system based on winding vibration frequency response signal.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM41

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