Electrical aging phenomena of medium voltage EPR cable energized by ac voltage with switching impulses superimposed

Electrical aging of polymer insulated power cables has been an important subject of investigation in the last several decades. Cable insulation is placed under heavy electrical stress due to overvoltages occurring during switching operations taking place in the power system. Transients overriding the normal ac operation voltage are some of the most hazardous conditions for cable insulation life. Although a good understanding of aging mechanisms under single stress has been achieved, more research work is needed to fully grasp the phenomena taking place under multi-stress conditions. In this study, the electrical aging of 15 kV Ethylene Propylene Rubber (EPR) power cables was undertaken by ac voltage with switching impulses superimposed in wet condition. The experiments aimed at providing a better understanding of the electrical aging phenomenon of EPR cable insulation in wet condition. It also helped to assess the reliability of EPR cables used under such circumstances.