College of Information Science and Engineering, Huaqiao University, Xiamen 361021, China.
Math Biosci Eng. 2021 Feb 25;18(3):1966-1980. doi: 10.3934/mbe.2021102.
This study aimed to propose an equal-integral-bandwidth feature extraction method based on fast Fourier transform (FFT) to solve the problem of cumbersome processing and a large amount of calculation in the common feature extraction algorithm for vibration signals of on-load tap changer (OLTC). First, the vibration signals of OLTC were preprocessed in segments, which highlighted the status features and avoided the shortcomings of the FFT spectrum that lacked time axis information. Second, the vibration signal segments were analyzed with FFT, and the generated signal spectrum was divided into several segments according to equal integral. The bandwidth coefficient obtained in each segment was the characteristic value. Third, this study proposed that adding appropriate time domain features and further improving the algorithm could improve the accuracy of fault diagnosis. Finally, the main mechanical faults of OLTC were simulated, and the vibration signals were collected to carry out the fault diagnosis experiment of OLTC. The results showed that the FFT-based equal-integral-bandwidth feature extraction method was simple in processing, small in calculation, easy to implement in an embedded system, and had a high accuracy of fault diagnosis.
本研究旨在提出一种基于快速傅里叶变换（FFT）的等积分带宽特征提取方法，以解决有载分接开关（OLTC）振动信号常用特征提取算法处理繁琐、计算量大的问题。首先，对 OLTC 的振动信号进行分段预处理，突出状态特征，避免 FFT 频谱缺乏时轴信息的缺点。其次，对振动信号段进行 FFT 分析，并根据等积分将生成的信号频谱分为若干段，在各段中得到的带宽系数为特征值。第三，本研究提出在各段中添加适当的时域特征，并进一步改进算法，以提高故障诊断的准确性。最后，模拟 OLTC 的主要机械故障，采集振动信号进行 OLTC 故障诊断实验。结果表明，基于 FFT 的等积分带宽特征提取方法处理简单，计算量小，易于在嵌入式系统中实现，故障诊断精度高。
