7.1 INTRODUCTION

In Chapters 5 and 6 we discussed about steady state and dynamic frequency deviation. For a normal system operation the maximum permissible limit of frequency deviation is ± 0.5 Hz. For a satisfactory operation of the system we need some control strategy that keeps the deviation to a minimum. A commonly used controller is a proportional plus integral controller. Whenever load varies, the presence of an integral controller aids us to bring the steady state frequency deviation to zero with faster dynamic response. However, due to load variation the system loses its economic operation and hence, in addition to an integral controller, an economic dispatch controller should also be present for a satisfactory operation of the system.

In this chapter we shall discuss the steady state operation of a single-area system, initially with an integral controller, and later with economic dispatch control.