This dissertation is, in the main, concerned with the synthesis of excitation feedback controllers designed to improve the performance of a.c. turbogenerators following a large disturbance. Solution methods and approaches for nonlinear optimisation are outlined and their application to a single-machine power system is considered. Linear search algorithms are applied to the optimisation studies of single variable excitation control. With the aid of signal-flow graph and Bode diagram techniques, a new single state variable for feedback has been made obvious. Dynamic sensitivity method has also been used to investigate the suitability of all the feedback signals under study. The theoretical excitation control laws obtained have been confirmed on a small, but realistically scaled, laboratory-model power system. Finally, multi-variable optimisation is applied to coordinated excitation and steam-flow control. Only one extra stabilising signal has been added to each of the two control loops. It has been found that substantial improvements in transient performance can be achieved by the suboptimal control laws derived, under large disturbances and different operating conditions.
|Date of Award||1979|