SUBOPTIMAL CONTROL ON LINEAR SYSTEMS

Abstract

One of the major problems arising in interconnected power systems is that of coordinating voltage regulators and governors to obtain suitable dynamic stability characteristics. This dissertation deals with the suboptimal control theory applied to such a system. The system chosen is salient pole 8ynohro-nous machine with infinite bus bar equipped with voltage regu- lator and hydraulic governor. The systems is linearised by small perturbation technique. A control signal 111 actuates the voltage regulator and signal 132 actuates the hydraulic governor. The system equations are framed int sete space representation form [1) = [A] [xj + [3] (u] and Quadratic cost functional Y J = $ /f(X' Q xJ +[U' R u]Jr dt ✓o is chosen as performaaoe Index to system. Concept of cuboptimai control theory is introduced and an illustration is pres~ntod for acquainting the theory in deep. Then the above system is designed using suboptimal control. The transient behavior of all the states of the system with and without suboptimal control are com-pared and it is found that initially oscillatory system becomes stable.