Method of identifying weak transmission network stability boundaries

Methods of determining weak transmission stability boundaries are developed based on the strong controllability and observability properties of power systems. This theory has been previously applied to a dynamical model of the generators and network. It was established previously that the network and generator states associated with a cluster of generator and load buses surrounded by weak transmission boundaries are strongly controllable and observable for a single measurement and control at generators or load buses in that bus cluster. Such a bus cluster is called the control area. Two methods of determining control areas, where strong controllability and observability hold, are developed. Both methods attempt to determine weak transmission stability boundaries that encircle control areas. The groups of generators identified as belonging to each control area is identical to the groups of coherent generators determined using a RMS coherency measure evaluated for the set of all inertial load flow contingencies