The insulation of the high voltage power cable will be placed under higher electrical stress by switching surges during the power system operation. The switching surge weakens the power cable insulation and it leads to failure of cables. It has a significant effect on the aging of the insulation material that affects the lifetime of the power cables. This research studies the electrical degradation of 15 kV XLPE and EPR power cables insulation by applying 100, 500, 1000 and 5000 switching impulses of 100 kV. The status of the polymer cable insulation aging is evaluated by the measurement of partial discharge level and ac breakdown voltage. Partial discharge measurements are taken throughout the aging process at specific intervals of applied impulses. The ac breakdown voltage is also measured at the end of the accelerated aging process.