Deep Trap Sites Suppressing Space Charge Injection in Polycyclic Aromatic Compounds Doped XLPE Composite

In this study, the space charge characteristics in the polycyclic aromatic compounds doped cross-linked polyethylene (XLPE) composite were analysed by integration current (Q(t)) method and quantum chemical calculation. Experimentally, the space charge behaviours of XLPE composites modified by the three selected polycyclic aromatic compounds during polarisation and depolarisation process at 25 and 80°C were measured by Q(t) method, respectively. The energy levels and 3D potential distributions of the three polycyclic aromatic compounds were calculated by density functional theory. The experimental and calculation results indicate that the polycyclic aromatic compound C with deep carrier traps and stronger polarity exhibits outstanding ability to reduce space charge injection than the others at both 25 and 80°C. Generally, 4,4′-bis (dimethyl amino) benyil has great potential as the organic additive for DC cable insulation from the view of space charge suppression.