This project investigates the synthesis of supervisory controllers for power system security applications in the framework of discrete-event systems (DES). In this context, the supervisor tries to prevent the occurrence of undesirable event sequences. New results address three central issues in power systems: (i) many events are not observable to the supervisor, (ii) the computational complexity of partial information supervisors can be prohibitive, and (iii) decision structures in power systems involve multiple supervisors having access to different information sets and controllable event sets. Results include necessary and sufficient conditions for centralized and decentralized (a set of local supervisors and a fusion strategy) supervisors and an explicit algorithm for constructing supervisors that meet the sufficient condition. The supervisors (centralized and local) can be implemented on-line and the computations can be performed in O(mn) complexity where n is the number of states and m is the number of events. The set of local supervisors has desirable properties for all fusion rules within a class including the OR rule, the AND rule and the majority rule. Examples considered include a simple distribution network restoration problem and a more extensive problem of transmission system restoration in which it desired to maximize the network security level.

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