Space charge characteristics of XLPE and semiconductive layer coated with graphene

Space charge can affect significantly the reliability of DC cross-linked polyethylene (XLPE) power cables. For limiting the injection and accumulation of space charge, specimens with graphene coating applied on a sandwich composed of XLPE and semiconductive layer were made. Space charge distribution of specimens was measured at 10 and 40 kV/mm. The measuring results show that when graphene is coated on the semiconductive side, negative charge accumulates in XLPE, and the quantity of positive charge injected from anode is significantly reduced. When XLPE is coated with graphene, little space charge is injected into XLPE, and positive charge accumulates near the interface of XLPE and electrode, which lowers electric field near the anode.