Grid frequency (60 Hz in North America) / frequency regulation

The electric grid operates at a specific alternating-current frequency, 60 Hertz (cycles per second) in North America and 50 Hz in most of the rest of the world, and every generator connected to the grid must stay synchronized to that frequency. Frequency regulation is the continuous, moment-to-moment balancing act of adjusting generation to match demand precisely enough to hold that frequency steady; if generation and demand fall too far out of balance, frequency drifts, which can damage equipment and trigger automatic protective shutdowns.