电站锅炉声学测温中时间延迟估计的仿真研究  

Simulation of Time Delay Estimation in Acoustic Pyrometry in Power Plant Boiler

作　　者：沈国清[1] 安连锁[1] 姜根山[1] 梁亚园 张达勋 

机构地区：[1]电站设备状态监测与控制教育部重点实验室(华北电力大学),北京市昌平区102206 [2]张家口发电厂,河北省张家口市075133

出　　处：《中国电机工程学报》2007年第11期57-61,共5页Proceedings of the CSEE

基　　金：国家自然科学基金项目(10574043);教育部高等学校博士学科点专项科研基金项目(20050079004)。~~

摘　　要：为了在电站锅炉声学测温中获得准确的声波飞渡时间，针对强噪声环境下弱信号检测问题，研究了声信号的时间延迟估计。对从国内某电站锅炉采集的炉膛噪声进行了频谱分析和统计分析，认为炉膛噪声是以中心频率250-1000Hz的低频燃烧噪声为主的类高斯噪声。指出了电站锅炉环境下几种传统的时延估计方法的不足，提出了一种基于高阶累积量的时延估计方法。在指数分布信号中加入实测炉膛噪声信号，设定不同的信噪比，分别对基于ML互相关方法和基于3阶累积量方法进行了100次蒙特卡罗时延估计仿真试验。结果表明，在较低的信噪比下，3阶累积量方法仍可以抑制非高斯信号中相关高斯噪声的影响。不仅为声学测温中的声波飞渡时间测量提供了指导，而且对基于时延估计的锅炉四管爆漏声源定位有一定的参考价值。In order to acquire the accurate transmitted time of sound wave in power plant furnace in acoustic pyrometry, the time delay estimation （TDE） of weak sound signal under the condition of strong noise is studied. Spectral analysis and statistic analysis of the background noise in furnace, acquired from a power plant boiler in China, are done. The result shows that the background noise in furnace is dominated by the combustion noise with center frequency from 250 to 1000 Hz and with Gaussian-like distribution. The disadvantages of some traditional methods of TDE are shown. A new TDE method based on high-order cumulant is given. The acquired background noise in furnace is added to signal with exponential distribution. One hundred Monte-Carlo simulation tests of TDE are done based on the ML cross-correlation method and high-order cumulant method respectively under different signal noise ratio （SNR）. The result shows that the influence of correlated Gaussian noise can be restrained from the non-Gaussian signal based on the third-order cumulant method even under poor SNR. It is useful to the measurement of transmitted time of sound wave in acoustic pyrometry and to the sound source location of ＇four-tubes＇ leaking in boiler based on TDE.

关 键 词：声学测温 时间延迟估计 互相关 高阶累积量 锅炉 

分 类 号：TK31[动力工程及工程热物理—热能工程]