Effect of Delocalized Structure on Voltage Stabilizer to Improve Electrical Performance of Cross-linked Polyethylene

This study proposes the inclusion of a novel voltage stabilizer to crosslinked polyethylene (XLPE) for improving the insulation performance of XLPE cables at higher voltage levels. The m-aminobenzoic acid and leucine were selected as voltage stabilizers to blend with XLPE base material, respectively. Thin film samples of about $\sim200\mu$m were prepared through a hot press method. Various electrical tests such as DC breakdown, DC conductivity, space charge distributions and surface potential decay were performed under $30^{\circ}\mathrm{C}, 50^{\circ}\mathrm{C}$ and $70\circ \mathrm{c}$. The trap distribution and the quantum chemical properties were calculated to study the mechanism. The results demonstrate that the addition of m-aminobenzoic acid can effectively improve the breakdown strength of XLPE, reduce the DC conductivity and space charge accumulation. However, the addition of leucine has no significant effect. The charge trap analysis indicates that the lower energy level traps are more advantageous to enhance the electrical properties of the material, while the quantum chemical calculation demonstrates that the delocalized structure dissipates the energy of the carriers. Thus, the delocalized structure of voltage stabilizer can effectively protect the XLPE molecular chain from the influence of high-energy charge carriers and hence improves the electrical insulation performance of XLPE.