Real-time optimal power flow in automatic generation control

The authors describe the concept, mathematical formulation, and solution of a real-time OPF (optimal power flow) in an energy management system. The real-time OPF replaces a classical real-time economic dispatch whenever a network flow violation occurs. To meet performance requirements (solution speed and frequency of execution) a two-stage approach is proposed. A full OPF is first executed in a nontime-critical mode and the critical branch flows are determined. Then, a constrained economic dispatch is executed based on the critical constraint set determined during the first stage. The execution frequency of the second stage is the same as the execution frequency of a standard real-time economic dispatch