Analysis on the Behavior of Protection of 500kV Breaker Protection

This paper described the inherent mechanism of 500kV breaker protection operation. Analyzed the breaker protection action sequence based on the relay protection equipment action report and fault wave in chart recorder. Conducted the fault replay experiment on the logic of software and circuit configuration about communication triple trip. The results show that relay contacts blocking is the primary cause of breaker protection mal-operation, which is verified by microscope examination, X-ray inspection and SEM mechanical tests. Finally, this paper proposed the precautionary measures from three aspects included equipment manufacture, field installation, operation and maintenance.