Guiding a power system restoration with an expert system

Minimizing the amount of time needed to restore a power system helps reduce the economic cost and the public's resentment over the interruption of service. An expert system can help the operator achieve this goal by providing actualized restoration plans, dependable recommendations, and a clear picture of the situation. A hierarchical structure has been adopted for the prototype expert system described. This structure separates the selection of the next objective (strategic reasoning) from the development of a plan showing how this objective can be achieved (tactical reasoning). This separation enables the system to quickly adapt its recommendations when a problem arises during the restoration. Planning connection paths through substations of widely different configurations is greatly facilitated by the adoption of a hierarchical description of the topology of these substations. This knowledge representation scheme is the symbolic equivalent of the one-line diagrams used by the operators.