Aging failure model of circuit breakers equipped with condition monitoring systems

Lifetime management of circuit breakers (CBs) compared with the other components in power system is dependent not only on the natural age but also on the number of operation, applications, and maintenance scheduling. In addition, condition‐monitoring systems (CMSs) are widely used to extend lifetime and improve the quality of maintenance. However, the employing CMSs for CBs are faced with economical and technical challenges. This paper presents a new probabilistic aging failure model for CBs equipped with CMS. The proposed model improves the conventional approach for the assessment of efficiency of maintenance strategies using available filed data and coupling some weighting factors. The model is based on the state diagram along with Monte Carlo simulations to provide more flexibility in quantification of practical concerns. The model helps us to compare all maintenance strategies within 1 framework to select the best policy with respect to working situation of CBs. The approach has been compared and verified with the conventional aging model. Moreover, it is numerically applied to 2 common types of CBs, that is, SF6 and minimum oil based on the field data to reveal the results of considering the real aging and dynamic behavior of CBs on cost/benefits of maintenance policies. The results of applying the proposed approach to CBs indicate that ignoring the realistic situation of CBs results in a significant underestimation or overestimation of reliability and consequently making a wrong decision on installation of CMS or even in selection of the optimum inspection time.