SIMULATION AND ANALYSIS OF A POWER PLANT FEEDWATER SYSTEM

With a view to studying improved control systems in a power plant feedwater system a suitable process and control system model was developed. This model bridges the gap between existing design and empirical models. The model is based on first principles. The primary governing factors are taken into account to ensure that the response to transients is correct but secondary factors are neglected to reduce the model complexity. It is shown that the lack of such secondary factors does not detract from the validity of the model when it is used for the analysis of control system response.; Modelling principles are outlined and the development of the model is described. Various computational routines to obtain satisfactory convergence are compared with emphasis on maintaining a logical program format. The computer model is subjected to various transients to demonstrate its capability of handling a range of disturbances with the correct response and where possible validation against real plant data is carried out. An analysis of controller tuning under different physical conditions is given as well as the effect of noise on the controller response. The application of conventional control systems with provision for sensor and actuator failures is considered and demonstrated to be advantageous.; The conclusions reached are that there are definite benefits in the addition of intelligent control systems in power plants but that it would be advantageous to study the overall plant system including the turbine and steam generators since the greatest improvements can be made at the main interfaces between major items of plant.