A comprehensive study of outage rates of air blast breakers

This paper presents results of an extensive study launched by Hydro One Networks aimed at determining air blast circuit breaker reliability measures from a statistical analysis of outage data. The study examines how the breaker failure rate depends on such factors as equipment age, voltage level, manufacturer, and number of repairs. Planned outage rates due to equipment maintenance were also investigated. Results presented in this paper are based on outage records involving 318 breakers and covering a period of 12 years. The results can form input information for probabilistic risk analysis studies.