Study on the Contact Resistance and Temperature-rise Performance of High-voltage Vacuum Interrupter

The temperature rise under continuous current is one of limitations on the development of vacuum interrupters (VIs). The contact resistance is one of the main heat sources. As a traditional contact resistance model, the conductive bridge is widely used in thermal simulation of medium-voltage and low-voltage contacts. Only the shrinkage resistance exists in the high-voltage vacuum contact, and the diameter of the contact is quite large, which means the influence of the current path on the contact plates is much more significant. In order to study thermal characteristics of high-voltage VI, a three-dimensional model was established and the conductive bridge was then verified by simulation and experiment. The results indicated that the traditional single conductive bridge could not accurately represent the contact resistance of high-voltage vacuum cup-type contacts. On the basis of the traditional conductive bridge, the number and position of the bridge were changed, and the simulation results were more consistent with the experimental values. Based on the multiple conductive bridges, the steady-state temperature-rise performance of high-voltage VI was analyzed through electromagnetic-thermal-flow coupling simulations. The results showed that the temperature rise of the contact plate was the highest, which was 296.83K, and the temperature gradually decreased from the contact plate to the conductive rod.