基于图像特征的电站锅炉空气预热器热点检测系统

空气预热器是火力发电机组重要的热能交换设备，由于燃料的不完争燃烧以及低负荷或停炉后空预器内气体流速低造成散热条件变差等原因，会引起空气预热器的再燃烧事故。针对现场环境，用低照度CCD获取了空气预热器金属部件在不同温度下图像信息，借助于傅里叶变换，通过对频谱进行分析．得到了两组特征集，采用具有距离特征的类别可分性判据，对空气预热器不同的工作状态进行识别。试验表明，该方法准确有效，基于该方法的系统已经成功应用于国内外200MW以上的火力发电机组中。

Power Boiler Air Preheater Hot Spots Detection System Based on Image Feature

Rotary air preheater is the important heat exchanger in power plant units.Recombustion accident can be caused by inadequacy combustion of fuel or badly heat-dispersed condition aroused by low air or gas velocity after boiler outage.The low-luminosity CCD camera has been used to obtain image information of air preheater heat transfer elements at different temperature levels.Two groups of feature subsets have been gotten by frequency spectrum analysis based on fast Fourier transform (FFT).According to classified separability criterion,it can be achieved to distinguish different status of air preheater.Experiments prove that this approach is veracious and effective and the system based on this approach has been gone into many practical applications in boiler of 200MW capacity or above successfully in China or abroad.