为了准确判断热力发电厂出现运行参数偏离设计工况的异常状态的原因是由于系统变工况，还是设备故障所致。基于在役核电厂汽水分离再热器（MSR）设计参数，采用THERMOFLEX软件构建热力设备计算模型，实现软件变工况计算并与电厂实际运行数据对比。结果表明，热力设备计算建模的变工况计算结果与实际运行数据的误差在1%以内，能较快地确定运行参数偏离设计的根本原因，实现了对MSR设备运行异常的快速诊断，该方法也可拓展应用于其他热力设备的变工况计算与性能诊断。

When the thermal power plant experiences an abnormal condition in which the operating parameters deviate from the design conditions,it is difficult to determine whether it is an operation adjustment or equipment failure due to the complexity of the thermal system and equipment operating under variable conditions.Based on the design parameters of the Moisture Separator Reheater(MSR)in the nuclear power plant in service,THERMOFLEX software was used to construct the thermal equipment calculation model.The comparison of the software variable working condition calculation and the actual operation data of the power plant is realized.The results show that the thermal equipment modeling and variable condition calculation methods described in this paper have an error of less than 1% between the calculated results and the actual operation,which quickly locates the root cause of the deviation of the operating parameters from the design and diagnoses the abnormal operation of MSR equipment.This method can be extended to the calculation of variable operating conditions and performance diagnosis of other thermal equipments.

TK172