How do dispatchers prevent service interruptions?
Supply and demand must be perfectly in balance. Even small imbalances can cause voltage levels to swing significantly. To prevent damage, the grid is designed so that whenever unacceptable fluctuations in voltage levels or frequencies begin to occur at any point in the system (due to lines de-energizing), the generation in the area will immediately shut down. When shutdowns occur at the powerplants, the connections to adjoining areas are designed to automatically isolate the area where the imbalance occurs from the rest of the grid. So power that had been flowing over the line that failed automatically shifts to other, adjacent lines, reducing the risk of interrupting service to end-use customers or overloading lines.
