Analysis of contact ablation of circuit breaker after short circuit current breaking

Abstract

During the opening and closing process of the contact, it will undergo repeated arc ablation and wear. After each ablation and wear, the composition, performance, and shape of the contact surface constantly change, leading to cracks, slag drop, melting, evaporation, and other phenomena on the contact surface, ultimately causing the contact to fail, resulting in the switch not being able to open and close normally. In order to study the failure mechanism of arc contacts caused by arc erosion after breaking short-circuit current, a pair of arc contacts for the cumulative breaking short circuit current test was selected as the research object. The metallographic, microscopic morphology, and energy spectrum analysis of the arc contacts were conducted, and the analysis results were compared with the new arc contacts to reveal the evolution and development process of arc contacts from cumulative arc erosion to failure during breaking.