الفهرس 
AbstractOnly 14 pages are availabe for public view
 |  | from | 138 |  |  |
| | | from | 138 | | |
Abstract
The construction of thermal power plants had in the last years a very
quick development. The power of the single block plant unit increased with a high progression. As a consequence, the utilization of natural circulation. boiler or once through boiler on large steam generators has required the use of ’automatic control systems which give a higher operation safety besides meeting
One of the main steps in the design of boiler control systems is the
Modeling of steam generators. Previous work studied the control system eling modeling neglecting the time taken by the actuators although all actuators are . mechanical systems either pneumatic or hydraulic.
this work a new mathematical model for steam generators is introduced. This el is based on the principles of mass, volume and energy balances. Stec.dy are considered and are calculated through the model To verify the accuracy of the model, it is compared with another theoretical Model. The comparison shows that the present model is more accurate. Then the model is applied to the available readings from Damanhour Thermal power Plant, and the results from the model with the plant performance during dynamic test are compared. The comparison shows that the model
performance can represent the actual. The model is used to design more accurate control loops for steam ators. The control loops considered in this work are the superheated steam ure control and the drum water level control.
An optimization technique is used to get the optimal parameters of control Elements. The dynamic responses of such control loops are shown for different It is found that using traditional drum level control, a problem may due to the shrink and swell phenomena. So the three elements drum control is suggested and tested for the model. Problem of drum level control instability using three elements control in of superheated leakage or feed water loss through the continuous blow down. It tested and the maximum permissible percentage leakage is calculated.
. The Optimum control loops are compared with that of Damanhour Thermal r Plant during runback test and the comparison shows that the optimum control loops suggested are better.
The procedure for the design of optimum PI (proportional integral) rollers is by constructing the model with fixed parameters. These optimum eters are obtained for certain operating condition if this condition changes ri’system performance will not be optimal. So an adaptive control system is ted to control the superheated steam pressure and the drum water level. br>. The Main steps in the design of boiler adaptive control system are discussed and, Comparison between adaptive control and optimal control systems is given.