What is the primary purpose of Automatic Generation Control (AGC) in power systems?

The primary purpose of Automatic Generation Control (AGC) in power systems is to regulate the power output of generating units to maintain system frequency. AGC is an essential feature in the operation of the electrical grid, as it helps to balance supply and demand in real-time. By monitoring the frequency of the system and the power flow, AGC automatically adjusts the generation output from power plants to ensure that the frequency remains stable around its nominal value (typically 60 Hz in North America or 50 Hz in many other parts of the world).

This process involves signaling generating units to increase or decrease their output based on real-time load conditions and frequency measurements, thereby ensuring a reliable and stable electricity supply. A well-functioning AGC system enhances grid reliability and helps prevent frequency-related disturbances that can lead to blackouts.

The other options provided do not capture the core function of AGC. Increasing overall generation capacity relates to long-term planning and resource allocation rather than real-time regulation. Performing regular maintenance and scheduling preventative repairs are essential components of power plant management but do not involve the automatic regulation of power output or frequency control.