RETEX (RElay Testing EXpert): an expert system for analysis of relay testing data

A new expert system application to power system protective relay evaluation testing, a crucial but time-consuming engineering task, is presented. An expert system called RETEX (relay testing expert) has been developed as a computer aid for analysis of relay testing data. A knowledge base for relay testing data analysis has been developed. A relay logic model is used to determine the expected relay operation for simulated faults. Hierarchical test reports and comparison reports can be automatically generated by RETEX, which is designed with basic language processing capabilities. The generality necessary for handling various relay models is provided by a description file approach. The expert system is implemented in a rule-based and object-oriented architecture with the expert system development tool NEXPERT Object. The feasibility of the prototype has been demonstrated with Bonneville Power Administration (BPA) relay testing data