Trap Distribution and Space Charge Behavior of PP/ULDPE/ Radical Scavenger Composites for HVDC Cable Insulation

Space charge and breakdown behavior are important factors in the design of high voltage dc (HVDC) cables. Since the working temperature together with additives has a great influence on the insulation performance of the composites, the temperature effect investigation would be highly beneficial. In this paper, the space charge test of the polypropylene (PP) /ultralow density polyethylene (ULDPE) blends and its radical scavenger modified composites are performed at 30, 60 and 90 °C, respectively. The trap distribution in the radical scavenger and the composites are investigated based on Quantum chemistry calculation and isothermal discharge current (IDC) test. The radical scavenger can introduce traps with different energy levels, which has greatly inhibited the space charge accumulation aggravated by the increasing temperature in the PP/ULDPE (PU) blends. The PP/ULDPE blends with 0.3 wt% radical scavenger exhibit great space charge performance for HVDC cable insulation.