Expert System for Initial Stage Restoration from System blackout of EHV Power System

Abstract

In this paper, an expert system was developed for initial stage restoration of EHV power system from system blackout. The operations to be done in case of blackout, are usually determined at every electric station by operation rules, and the power system is restored to the prefault state by carrying out the determined operations at each electric station. In case a regular operation should not work well, several supplementary operations are prepared. This method has some merits that it can restore along normal operation state, that its logic is simple, etc. Because of these merits, a part of the operation rules have been automated by automatic restoration equipments, but in case of system blackout, such human judgements as to secure initial power source are required, and operations by commands from a load-dispatching office become dominant. In this paper, an outline of restoration process was firstly clarified through analysis of the operation rules. Next, the operation rules were transformed into production rules, and were put in order at every electric station. An individual knowledge base was prepared for each group of electric stations in construction of the expert system, and a proper order was introduced in choosing a station to be restored, by which vain search of rules was eliminated. The expert system was applied to a model power system, and it was shown that the computation time for generating all restoration operations is about 0.5s, and that the system can deal with cases where there are some damaged equipments.