Power System Operation and Control

4.1 INTRODUCTION

In general, both active and reactive power demands change continually with the rising or falling of load. In order to meet the active power demand, inputs to the generators i.e., steam for turbo-generators and water for the hydro-generators must be regulated. Otherwise, the machine speed will vary with consequent change in frequency, which may be highly undesirable. Similarly, the excitation of generators must be continuously regulated to meet the reactive power demand. Otherwise the voltage at various system busses may go beyond the prescribed limits. In large interconnected systems, automatic generation and voltage regulation equipments are installed for each generator because manual regulation is not feasible. While changes ...