Intelligent Failure Diagnosis for Gas Circuit Breakers Based on Dynamic Resistance Measurements

Abstract

Moving and fixed main and arc contacts used in circuit breakers (CBs) are prone to erosion with time and usage. Static resistance measurement and dynamic resistance measurement (DRM) are well-known noninvasive methods for the condition assessment of the contacts. Practically, the implementation of various failures on contacts of the CB is so difficult due to their placement in a high-pressure interruption chamber. This paper investigates the impacts of common failure modes such as erosion, disconnection, and misalignment of contacts on DRM profile through 3-D multiphysical simulation of the interruption chamber in the finite-element analysis software COMSOL. The model has been verified against experiments conducted on a 24-kV, SF6 CB with a high-resolution scope. The measured profiles indicate that DRM exhibits specific behavior with respect to each failure, e.g., the arc contact erosion leads to a change in the commutation point in DRM. The results have been organized into an intelligent failure diagnosis algorithm based on a set of DRM-based features. In the end, the performance of the proposed algorithm which could be suitable for smart grids is evaluated in the case of an experiment.