Electrical Degradation of High Voltage Cable Insulation Energized by Switching Impulses

The electrical degradation of cable insulation in distribution lines is due to the electrical stress caused by switching surges. During the operation, the insulation of power cables will be placed under high electrical stress, including overvoltages caused by switching. The status of power cable insulation aging is evaluated by the measurement of partial discharge level and AC breakdown voltage. The study helps to determine the reliability of power cables, as well as an estimation of the cable's expected lifetime. Many other factors than aging by switching surges have to be also considered as effect of the electrical insulation degradation.