Abstract
This paper presents a diagnostic method of power system using logical constraints and a diagnostic system based on this idea. Logical constraints represent causal relations and hierarchy relations among states. These logical relations are derived from initial causal relations and primitive relations among basic state elements. First step of this method is to generate additional causal relations for efficient inference in case that both causal relations and hierarchy relations exist. Next, definite and possible states are generated. Information which means direction of inference is attached to states and used in this process. Also, inference processes to find out explanation roots between states and to verify a possible cause are applied. Finally, preference solution is selected. If preference solution is considered as a possible cause, next preference solution is infered after negating the prefarence solution.
