Temperature rise of canted spring contacts during fault current

Abstract

During the breaking test of a high voltage circuit breaker, a canted spring contact connecting the busbars of the switchgear melted. This event provided a good opportunity to test the reliability of finite element (FE) temperature rise calculations based on a transient coupled thermal-electromagnetic (EM) model. To properly include the Joule-losses at the tiny contact points in a time-varying ANSYS FE analysis, we had to devise a unique method of contact resistance modelling. The paper shortly describes this method and shares our experience we obtained from the case study of canted spring contact temperature rise.