Operational experience and maintenance of online expert system for customer restoration and fault testing

The online operational experience is reported for CRAFT (customer restoration and fault testing), a rule-based expert system capable of locating the faulted section of a transmission line based on the status of breakers and automatic switches. The authors propose a methodology for maintaining rule-based expert systems. The following capabilities were incorporated: detecting the relations of conflict, redundancy, etc., to maintain consistency of the rule base, tracing the reasoning process to understand the problem solving approach, and reducing the size of test cases after changes are made to the rules. The generic maintenance procedure has been implemented for the CRAFT system