Supervisory control of electric power transmission networks

The methodology of discrete-event systems (DESs) and supervisory control is applied to a line-restoration problem, aiming to increase the steady-state security level of a power network during restoration. An example using the IEEE 14-bus system serves to demonstrate the potential of the DES formulation in the control of power networks, and to introduce the basic tools and techniques that this formulation offers. Unlike other types of controllers, a DES-based supervisory controller does not serve to specify the exact control action at each state of the network. Rather, it defines an envelope of allowable actions. Within that envelope local controllers make specific decisions to satisfy local performance indices. This approach allows the creation of multi-level non-conflicting hierarchical control procedures, which are particularly attractive to managing large-scale systems. Each level in the hierarchical control structure defines the envelope of operation for the lower-level controllers through the enabling and disabling of controllable events. Component failure such as line or generator outages are formulated as uncontrollable events. Synthesis procedures for DES-based supervisory controllers can then be applied to synthesize hierarchical control for large power networks.