Influence of aging mode on space charge distribution of AC XLPE cables

In order to investigate the relationship between the aging state of HV AC XLPE cable and the characteristic of space charge of XLPE, we studied the space charge distribution of HVAC XLPE cables under different aging modes. Moreover, we adopted pulsed electro-acoustic (PEA) method to measure the evolution of space charge inside the insulating materials that were got from different position of AC cables. It is found that the total charge amount of insulating materials from un-aged cables and cables under actual operation increases along the radial direction from inner to outer, while the total charge amount of insulating materials from accelerated aging cables decreases. Space charge of accelerated aging cables starts from the inside of the insulating materials, while it starts from the outside of cables aged under normal operation. It is suggested that the space charge characteristics of AC XLPE cable insulation varies with its aging state obviously, thus the space charge measurement can be used as an effective method for aging state assessment of AC XLPE cable.