Assessing the effect of maintenance on high-voltage circuit breaker reliability

The present work addresses the problem of the censoring effect of preventive maintenance on equipment re- liability. More precisely, a method is proposed to assess this effect for units featuring minor and major failure modes as defined in. Accordingly, the main postulate is that age-dependent major failures (random failures are not considered as they are not influenced by preventive maintenance) are initiated by a preceding minor failure of some kind. A standard genetic algorithm is used in order to estimate model parameters on the basis of a reference reliability curve for high-voltage circuit breakers. Moreover, confidence intervals for the parameter estimates are calculated by means of Monte Carlo simulation.