Behavior of post insulators during UHV dc test

This paper presents experimental results on post insulators subjected to ul tra high de voltages in the range of 1 to 4.8 MV. The behavior of new and a ged insulators has been studied recently during diagnostic and accelerated aging tests, in order to characterize both their withstand and recovery vol tages, as well as estimate their remaining life time. Estimation of their r emaining life time enables a better prediction of maintenance intervals, th us avoiding unnecessary and costly downtime periods. Measurements of the re covery voltage also have been performed on insulators presenting defects, f ollowing dielectric failure in service. The results of the accelerated agin g tests carried out demonstrates a faster assessment of the post insulators performance.