基于小波分析的300KA预焙阳极铝电解槽阴极状况的诊断

发布时间：2018-03-19 14:48

本文选题：铝电解　切入点：小波变换　出处：《北方工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：工业铝电解过程在电解槽内进行,电解槽的运行状况直接影响电流效率和能量消耗,掌握电解槽的运行状况至关重要。铝电解槽的运行状况与阴极状况有关,铝电解槽阴极软母线处的电压是反映槽况的重要参数之一。所以通过分析铝电解槽阴极软母线的电压研究阴极状况,对阴极状况做出准确的诊断具有重要意义。采用小波变换对采集到的铝电解槽阴极软母线的电压信号进行分析。分别从时域和频域两个方面对采集的电压信号进行分析。采用了能量对比实验法确定小波分解层数,对电压信号进行小波多尺度分解后,得到含噪声较少含主成分较多的第三层近似信号。时域上,先对第三层近似信号采用无量纲特征参数提取法得到特征参数,再对提取的特征参数应用K-mean聚类分析的方法,得到区别明显的有故障的一类数据和无故障的一类数据。但当诊断时间间隔缩小后验证此诊断方法的适用性时,故障识别率不能满足实际需要。频域上,对第三层近似信号的包络谱提取包络谱最大值特征参数,对包络谱最大值通过统计分析法得到的划分有无故障的临界值。用临界值对数据进行分类分析,将数据分为有故障的一类和无故障的一类,此方法通过了适用性的验证。最后,比较了时域和频域上两种诊断方法的优缺点,发现频域上对信号包络谱的最大值进行分类分析的诊断方法更优。故将此故障诊断方法应用到铝电解槽阴极状况诊断系统的设计中。诊断系统用MySQL存储采集到的数据并供Matlab调用;Matlab实现了导入MySQL中数据的功能、查看数据功能、绘制曲线功能、诊断功能。
[Abstract]:The process of industrial aluminum electrolysis is carried out in the electrolytic cell. The operation condition of the electrolytic cell directly affects the current efficiency and energy consumption. It is very important to master the operation state of the electrolytic cell. The operation condition of the aluminum reduction cell is related to the cathode condition. The voltage at the soft bus of the cathode of the aluminum reduction cell is one of the important parameters to reflect the condition of the cell, so the cathodic condition is studied by analyzing the voltage of the soft bus of the cathode in the aluminum reduction cell. It is of great significance to make accurate diagnosis of cathode condition. Wavelet transform is used to analyze the voltage signal of the soft bus in the cathode of aluminum reduction cell. The voltage signals collected in time domain and frequency domain are analyzed respectively. The energy contrast experiment method is used to determine the number of wavelet decomposition layers. After wavelet multiscale decomposition of voltage signal, the third level approximate signal with less noise and more principal components is obtained. In time domain, the dimensionless feature parameter extraction method is used to extract the third layer approximate signal. Then K-mean clustering analysis is applied to the extracted feature parameters to obtain a class of data with obvious fault and a class of data without fault. However, when the time interval of diagnosis is reduced, the applicability of this method is verified. The fault identification rate can not meet the actual needs. In frequency domain, the envelope spectrum of the third level approximate signal is extracted from the maximum characteristic parameters of the envelope spectrum. The critical value of the maximum value of envelope spectrum is obtained by statistical analysis. The data is classified and analyzed by using the critical value, and the data is divided into two categories: the one with fault and the one without fault. The method is proved to be applicable. The advantages and disadvantages of the two diagnostic methods in time domain and frequency domain are compared. It is found that the method of classifying and analyzing the maximum value of signal envelope spectrum in frequency domain is better. Therefore, the fault diagnosis method is applied to the design of cathode condition diagnosis system for aluminum reduction cell. The diagnosis system is collected by MySQL storage. The function of importing data into MySQL is realized by Matlab calling Matlab. View data function, draw curve function, diagnose function.
【学位授予单位】：北方工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ151

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