A Comparison of a Drum Boiler-Turbine Model to Measurements and Models Obtained by Identification

Abstract A selection of results from a study of models of drum boiler-turbine units is presented. The 160 MW unit P16-G16 at Oresundsverket Power Plant at Malmo, Sweden, was modelled as an example and the results are compared to those of experiments and identification. The model can be used for control, design as well as acceptance test purposes. Basic physical laws are applied to significant components of the drum boiler-turbine unit. The approximations and the general approach to the modelling procedure are presented but no details of equations are given«, The linear model on state space form is generated by a computer program from construction data«, Model inputs are fuel flow, control valve position, attemperator and feedwater flows. Model outputs are various temperatures, pressures, flows, turbine powers and drum level. Identification experiments on the 160 MW boiler-turbine unit were made in June 1969. The same inputs as in the model were used to excite the boiler. Only one input at a time was perturbed for security reasons© The measurement time for one experiment was 1 hour and the sampling rate 10 seconds. An elaborate comparison of a 9th order model and the real process responses to the five inputs fuel flow, control valve position, attemperator and feedwater flows is presented. Responses compared are those of active power, drum pressure, drum level, steam flow and steam temperatures. For the fuel flow-drum pressure and control valve position-active power loops also linear models obtained by maximum likelihood identification are compared to models from construction data. The agreement is in general good.