Assessment of 10kV HVAC cable under different aging modes by pulsed electro-acoustic method

Abstract

To investigate the relationship between aging mode and the characteristic of space charge distribution in cross-linked polyethylene (XLPE) AC cable, a full sized space charge measurement system was developed based on the pulsed electro-acoustic (PEA) method. Space charge distribution of cables aged under different conditions like thermal, water and dry atmosphere was studied in detail, as well as the aging factor acquired from the isothermal relaxation current (IRC). The effect of aging mode on space charge and the relaxation current has been discussed. It is found that there is an approximately positive correlation between the space charge amount and the aging factor. The position and amount of space charge accumulated inside the insulation vary sensitively with aging mode. The effect on space charge distribution under a certain aging mode has some common points. It can be seen that space charge of insulation aged in dry atmosphere locates more uniform than that aged in water and in thermal condition, and the charge amount of the latter two is more than the former. It is suggested that space charge can be used as an effective parameter for evaluating aging status of XLPE insulated cables with usual laying conditions.