Advanced generation control with economic dispatch

A new approach for the automatic generation control (AGC) of electric power networks is introduced. This approach also supports an economic dispatch feature which operates at a slower time scale and interacts with the AGC frequency stabilization function. AGC is separated into two subtasks: frequency regulation and tie-line flow control, and a hierarchy of controls are formulated to realize these two functions. The frequency regulation level, called secondary control, is decentralized, and optimized with respect to both frequency offset and change in generator governor controls. The tie-line flow control level, called tertiary control, is centralized, and works on a slower time scale than secondary control. Tertiary control compensates for inadvertent flows between areas by momentarily offsetting generator frequencies. These frequency offsets shift the phase angles found at tie-line terminals, and eventually realize the desired line flows. The role of economic dispatch (ED) is to reschedule the entire system to minimize overall generation cost. The proposed version of ED is centralized, and invoked at an even slower rate than tertiary tie-line regulation.