An expert system for diagnosis of digital relay operation

This paper presents an expert system which performs detailed diagnosis of digital relay operation by analyzing data contained in relay files and reports. Problem domain is discussed first. Then the analysis strategy is detailed: forward chaining reasoning, logic reasoning and backward chaining reasoning are employed to predict protection operation, identify unexpected protection operation and diagnose symptoms respectively. The implementation of knowledge representation by CLIPS rules is further described. Finally, an example is given to demonstrate the capability of the expert system