The conventional BTU correction logic has disadvantages of low capability of anti-load jamming and poor stability.Against this problem

the conventional BTU correction method and the one for modelbased soft measurement of coal calorific value were analyzed.Moreover

the operation data of a subcritical600 MW unit were used to carry out experimental verification for this BTU correction method for modelbased soft measurement of coal calorific value.The results show that

using the simplified nonlinear dynamic model of unit load-throttle pressure

the calorific value of coal was calculated

which can eliminate the effects of fuel flow variation and opening degree variation of turbine regulation valves on the coordinated control system.By employing the low-pass filter

the operation frequency of the BTU correction logic can be lower than that of the coordinated control system and the close-loop stability of all system can be guaranteed.The practical applications indicate this method has better dynamic and static stability

and the antijamming ability is higher.The calculation precision and lag time can satisfy the local demand and can be suitable for thermal power units with frequently changed generation load.