Sampled-Data Automatic Generation Control of Interconnected Reheat Thermal Systems Considering Generation Rate Constraints

This paper deals with some aspects of sampled-data Automatic Generation Control (AGC) of a two-area reheat thermal system provided with classical controllers. Discrete mode optimization of such controllers using margin of stability and Integral Squared Error concepts have been attempted. Investigations rev eal that the optimal integral gain achieved through the continuous mode analysis is totally unacceptable in the discrete mode for the sampling periods used in practice Moreover, for all practical purposes the optimum integral gain in the discrete mode can be achieved by neglecting the generation rate constraints from the mathematical model unlike in the continuous mode. Performances of discrete optimum integral and optimum proportional-integral controllers have also been examined. Recommendation to optimum sampling period selection has also been attempted.