以某电厂PG9171E燃气-蒸汽联合循环机组余热锅炉系统为研究对象，根据机组的热平衡图数据以及余热锅炉受热面的传热机理建立变工况模型，定义受热面的性能退化系数，建立故障诊断模型。利用建立的计算模型与故障数据计算出的结果，对机组低压汽水系统的异常现象进行分析诊断，可以明确看出低压蒸发系统出现异常。现场停机检查结果发现问题为低压汽包内部件脱落，导致汽水分离效果差，与理论分析结果一致，验证了计算模型的正确性。

Heat recovery steam generator (HRSG) system of a PG9171E gassteam combined cycle unit was selected as the research object in this work. Referring to the heat balance data of this combined cycle,the offdesign condition model of the steam system was established through the heat tramsfer mechanism of HRSG heating surface. The performance degradation coefficient of the HRSG heating surface was defined and the fault diagnosis model was established. Using the established calculation model and the calculation result of fault data,the abnormal phenomenon in the lowpressure evaporator was analyzed and diagnosed. According to the results,it could be clearly seen that there is an abnormality in the lowpressure evaporator. The onsite shutdown inspection results show that steamwater seperation effect is poor because of internal component falloff of lowpressure steam drum. The results are consistent with the theoretical analysis results,thus verifying the correctness of the fault diagnosis model.

TK229.92+9

国家科技重大专项（2017-I-0002-0002）