电力变压器振动特征监测与异常检测研究

发布时间：2018-03-15 23:34

本文选题：电力变压器　切入点：振动　出处：《华北电力大学》2014年硕士论文　论文类型：学位论文

【摘要】：电力变压器作为电力系统中最重要的设备之一,它的正常运行直接关系到整个电力系统的安全稳定。而在长期运行过程中,变压器铁心与绕组难免会出现异常,引发电力变压器故障。为了能及时发现电力变压器的故障隐患,提高电力变压器的运行可靠性,开展对变压器振动信号在线监测的研究具有重要意义。本文首先设计了电力变压器振动在线监测系统,采用LabVIEW软件开发了振动在线监测系统平台,实现了对变压器振动信号的在线监测,可实时不间断监测变压器油箱表面12个位置的振动信号,观测振动信号的主频、频谱图、趋势图等相关信息,并开发了历史数据分析模块,实现对电力变压器振动信号的全方位监测。基于频谱图对变压器不同测点处的振动信号进行了分析研究。研究发现,同型号变压器同一测点处的振动信号、变压器三相同一测点处的振动信号具有相似的特征频率,但各主频的幅值差异较大；变压器同相上下位置处的振动信号、同相高低压套管两侧对称位置处的振动信号在主要特征频率及各频率的幅值上都比较相似。因此在精度要求不高的情况下可以按上述结论减少测点,能够节约成本并且大大减少日后分析数据的工作量。基于小波包变换对变压器振动信号做了分析研究。根据小波包变换的原理,对待分析的振动信号进行3层小波包分解,将原始信号分解为8个不同频段的信号,分别提取其能量特征,构造其能量特征向量,将该向量与历史振动数据库提取出的指纹量进行对比,进而诊断出变压器铁心及绕组的运行状况。并采用该方法对一组振动信号进行了实例分析,其结果表明该方法可以有效诊断出变压器铁心及绕组的异常状况。
[Abstract]:As one of the most important equipments in power system, the normal operation of power transformer is directly related to the safety and stability of the whole power system. In order to find the hidden trouble of power transformer in time and improve the reliability of power transformer, it is of great significance to study the on-line monitoring of transformer vibration signal. In this paper, the on-line vibration monitoring system of power transformer is designed, and the platform of on-line vibration monitoring system is developed by using LabVIEW software. The on-line monitoring of transformer vibration signal is realized. The vibration signal of 12 positions on the surface of the oil tank of transformer can be monitored continuously in real time, and the main frequency, spectrum diagram, trend chart and other related information of the vibration signal can be observed, and the historical data analysis module has been developed. Realize the omni-directional monitoring of power transformer vibration signal. Based on the spectrum diagram, the vibration signals at different measuring points of transformers are analyzed and studied. It is found that the vibration signals of the same type transformers at the same measuring point and the vibration signals at the same measuring points of three phases of transformers have similar characteristic frequencies. But the amplitude of each main frequency varies greatly. The vibration signal at the symmetrical position on both sides of the in-phase high and low pressure casing is similar in the main characteristic frequency and the amplitude of each frequency. Therefore, if the precision requirement is not high, the measuring points can be reduced according to the above conclusion. Can save cost and greatly reduce the amount of data analysis in the future. Based on wavelet packet transform, transformer vibration signal is analyzed and studied. According to the principle of wavelet packet transform, the vibration signal is decomposed into 8 different frequency bands by three layers wavelet packet decomposition. The energy feature is extracted, and the energy feature vector is constructed, and compared with the fingerprint extracted from the historical vibration database. Furthermore, the operation condition of transformer core and winding is diagnosed, and a group of vibration signals are analyzed by using this method. The results show that this method can effectively diagnose the abnormal condition of transformer core and winding.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM41

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