A rule-based expert system with colored Petri net models for distribution system service restoration

A rule-based expert system with a colored Petri net (CPN) inference model is developed for service restoration of distribution systems. The CPN models of distribution components such as four-way line switches are proposed to derive the proper restoration plan after the faulted location has been identified and isolated. The unfaulted but out of service areas are restored by applying parallel-like reasoning in the CPN for multiple contingencies simultaneously. To assure the restoration plan can comply with the operation regulation, heuristic rules based on the standard operation procedures of Taipower distribution system are included in the best first search of the CPN. For the fault contingency during summer peak season, the load shedding is executed and the CPN models are designed to restore service to as many key customers and loads as possible. The priority indices of each feeder and service zone are determined according to the key customers within the service territory. A Taipower distribution system with 18 feeders is selected for computer simulation to demonstrate the effectiveness of the proposed methodology. It is found that the service restoration of distribution system can be obtained very efficiently by applying the proposed CPN model.