Lessons Learnt from Analysis of Tripping Records

The highest quality and performance demands are placed on protective relays since they must protect the expensive power system equipment from damage. The practice of protection engineering involves conducting periodic fault studies followed by protective relay setting, checking and co-ordination studies. Frequently, there is also need to carryout detailed post mortem analysis to investigate response of relays and breakers to certain system events. Post mortem analysis of tripping ensures the improvement in the relay setting, development of better protection schemes and also identifying the problems in commissioning of the protection scheme. This paper discusses the analysis results from some of the trippings occurred in the field and the lessons learnt from them.