Monitoring of protection system behavior using an expert system which analyses substations sequential events recordings. Field experience at Electricite de France

The authors have developed and experimented an expert system which performs protection system diagnosis using the sequential events recorded at substations. The diagnosis principle is based on a comparison of observed behaviour and the expected behaviour modelled in the knowledge base. This has been validated by use of a faults simulator which allows to reproduce multiple malfunctions of the protection system. In operation for more than 2 years in EDF, the SEPT system has managed to perform diagnosis of more than 200 incidents and has detected some protection malfunctions. A lot of work has been spent in maintaining the knowledge base to cope with the numerous changing of equipments and their settings. In the framework of generalizing the use of SEPT, the authors are studying a system which can help to easily build and modify the SEPT knowledge base