锅炉四管泄漏故障的仿真研究与智能诊断-控制工程专业论文.docxVIP

华北电力大学硕士学位论文 华北电力大学硕士学位论文 I I 摘 要 锅炉“四管”泄漏是指锅炉的过热器、再热器、省煤器与水冷壁由于过热、磨 损、腐蚀、焊接质量等原因而造成的管内工质泄漏。由于长期承受高温高压的运行 环境，四管泄漏是锅炉最常见的故障，不仅导致非正常停炉，带来经济损失，严重 时会危及运行人员的生命安全。由于锅炉内部汽水管道间相互连接，运行参数间高 度耦合，而且四管泄漏的故障现象具有一定相似性，同一故障随锅炉运行方式不同 现象也会有差别，因此故障发生后若要准确判定泄漏位置难度较大。若要依靠汽温、 汽压等运行参数准确判定故障发生位置，要求运行人员必须对不同运行模式下锅炉 四管泄漏故障发生后相关运行参数的变化规律及差别有深入了解。 本文借助 600MW 超临界火电机组仿真系统，针对不同运行模式，对超临界锅 炉四管泄漏故障开展了详细的故障仿真试验。在深入了解锅炉四管泄漏故障特征规 律的基础上，选取了与故障最密切相关的若干特征参数,并对故障特征参数进行预 处理，建立了故障知识库，完成了 BP 神经网络诊断模型的训练。利用训练好的诊 断模型，采用神经网络与征兆缩放技术相结合的智能诊断方法，在 MATLAB 环境 下编写了故障诊断程序，在火电机组仿真机上进行了详细的故障诊断实时仿真实 验。结果表明：该方法对四管泄漏故障可得到具有较高故障分离度的正确诊断结果， 可以准确及时地确定故障位置,具有较好的工程实用性。 关 键 词 ： 超临界锅炉；四管泄漏；仿真实验；神经网络；故障诊断 II II Abstract The boiler four-tube leakage faults refer to the working substance leakage in the tubes of superheater, reheater, economizer and waterwall inside the boiler，caused by overheating, wear, corrosion, subpar welding quality，et al. Due to the long-term operating environment of high temperature and pressure, four-tube leakage faults are the most common faults in a coal-fired boiler，which leads to not only abnormal shutdown, economic loss but also possible life-threatening to operating personnel. Because the steam tubes are connected to each other and the operating parameters are highly coupled,the phenomenon of the four leakage faults are with certain similarity. The phenomena of a same fault will be different under different operating modes. So the tube leakage inside the boiler is very difficult to be located accurately. In order to locate the leakage failure position depending on the steam temperature、steam pressure and other operating parameters, it is of great necessity for us to understand the changing rules of the four-tube leakage faults under different operating modes. With the help of a full-scope simulator, detailed fault simulation tests were carried out for the four-tube leakage faults of a 600MW supercritical boiler unit under different coordinated control modes. By selecting characteristic paramete