Effects of Radical Scavenger on Breakdown Strength and Space Charge Behavior of PP based Composites for HVDC Cable Insulation

Polypropylene (PP) has great potential to apply as insulation for extruded HVDC cables. This paper is intended to explore the effect of radical scavenger on breakdown strength and space charge in PP/ ultralow density polyethylene (ULDPE) composite. With the addition of radical scavenger, the breakdown strength of PP/ULDPE composites increases and the space charge accumulation reduces. The melting and crystallization temperature, as well as electric conductivity, show a little change, and the energy level and density of deep traps increases. It is shown that the PP/ULDPE/radical scavenger exhibit good breakdown strength and space charge performance for application in HVDC cable insulation. It can be attributed to that radical scavenger can capture free radicals during the increasing electrical stress.