Applicability of auxiliary contacts in circuit breaker online condition assessment

Circuit breaker (CB) due to its important roles in protection of power system has been recognized as a critical component. In order to assess the condition of CBs, a prevalent and conventional diagnosis method is time measurement of the mechanical operations (called timing test) through the travel curve (T.C.). However, it is an inappropriate technique for the online assessment. The major objective of this paper is to reveal the correlation between the T.C. and auxiliary contacts (A.Cs) of CB. On the basis the results, timing of A.Cs is proposed as easy-to-access, easy-to-measure, and non-invasive diagnosis parameters in online condition assessment of mechanism of CBs. The investigations are established upon measurements carried out on sixty CBs (72.5 kV, SF6) under healthy and faulty conditions. The new approach is conducted through an adaptive neuro-fuzzy inference system (ANFIS). The feasibility and applicability of the proposed method in CB condition assessment is verified against the experimental measured data.