The influence of current interruption operations on internal pressure in vacuum interrupters

Due to the impact of arcing on the high purity surfaces and bound residual gases, current interruption operations may influence the internal pressure in vacuum interrupters (VIs). In this paper, we investigate the temporal development of internal pressure in VIs immediately after a current interruption operation, non-intrusively using the magnetron method. By means of an experimental test setup that consists of a vacuum test system to vary the internal pressure in punctured, non-vented VIs with active getter materials, experimental test series were performed under variation of internal pressure and arcing time. The experimental results indicate that arcing during the interruption operation predominantly causes a significant decrease in the internal pressure of up to two orders of magnitude, depending on the arcing time and the initial pressure before the current interruption operation. We also discuss the impact of the observed pressure reduction effect on the possibility of predicting the remaining service life of installed VIs.