Effect of Thermal Aging and e-beam Energy on the Trapped Charge of Irradiated XLPE HV Insulation Cables in SEM

In the present paper we have used Scanning Electronic Microscopy (SEM) under vacuum conditions to show the influence of aging at high temperature and e-beam energy on the trapped charge in XLPE insulation. The XLPE samples are modeled and aged at 140 degrees C. Unaged and aged samples are charged with electron beam irradiation with three different energies: 5 keV, 15 keV and 30 keV. According to the overall results, thermal aging influences considerably the trapped charge in the material. It is found that the trapped charge increases with increasing aging time. The similar positive correlation has been noticed between the trapped charge quantity and the e-beam energy level. Overall, it is believed more shallower traps are generated under thermal aging because the modification of physico-chimical structure of the material leading to modification of depth and range of the traps.