CFC is necessary because the frequency of an electrical power system is influenced by several factors, including load changes, generation variations, and power transfers between different regions. To mitigate these effects, CFC systems employ various control mechanisms to adjust the active and reactive power flows within the system.
The primary objectives of CFC are:
Frequency Regulation: Maintaining the system frequency within a narrow band around the nominal frequency.
Load Following: Adjusting the generation to meet the changing load demand while keeping the frequency stable.
Spinning Reserve Control: Maintaining a certain amount of spare generation capacity to respond to sudden load increases or unexpected outages.
Inter-area Oscillations Control: Damping out low-frequency oscillations that may occur between different parts of the power system.
CFC systems typically consist of several layers of control, each acting on a different timescale:
Primary Control (or Governor Control): Responds rapidly to frequency deviations by adjusting the power output of generators within a few seconds.
Secondary Control (or Automatic Generation Control): Adjusts the generation set points based on frequency and tie-line power deviations to restore the frequency to the nominal value over several minutes.
Tertiary Control (or Economic Dispatch): Optimizes the generation schedule considering economic factors and transmission constraints to minimize operating costs.
CFC is an essential aspect of power system operation, ensuring the reliable and efficient delivery of electricity to consumers and industries. It involves coordination between different power plants, transmission networks, and control centers to maintain the delicate balance between generation and consumption, achieving stable frequency and power flows throughout the system.
