Integrating automatic generation control and economic dispatch for microgrid real-time optimization

A new scheme for real time operation of a microgrid comprising of thermal generators has been introduced. This scheme builds on the fact that economic dispatch can be converted from an optimization problem that is activated only in discrete instants of time into a feedback control problem that continuously adjusts the generators' set points. However, set point adjustment using control-based Economic dispatch (ED) is not sufficiently fast to maintain frequency deviation within acceptable levels. Hence, automatic generation control (AGC) is still needed to ensure fast action. It is shown in this paper that proper coordination between AGC and control-based ED gives rise to a control scheme that achieves efficient system frequency control while continuously operating the system in an optimal manner. A three generator system is used to implement the proposed scheme.