Study on the Influence of Temperature on the DC Electrical Properties of Cross-Linked Polyethylene Cable Insulation Materials

To improve the DC electrical performance of cross-Linked polyethylene (XLPE) cable insulation materials at high temperatures, this paper introduces 1,2-bis(maleimide)ethane (BMIE), which contains polar groups and multiple C-C double bonds functional structures, into the XLPE insulation system. The former can introduce dense and uniform deep traps, while the latter helps to graft onto the system to form a functional cross-Linked network. The XLPE samples with different modification contents were analyzed and studied. Fourier infrared spectroscopy, crosslinking degree tests and DC conductivity experiments were conducted on the samples. The results show that adding BMIE molecules can reduce the amount of diphenylperoxyphthalic anhydride (DCP) without affecting the crosslinking degree of the XLPE sample, thereby reducing the generation of crosslinking by-Products. The modified XLPE exhibits the lowest DC conductivity at different temperatures. Quantum chemical calculations indicate that the modified XLPE samples have positive electron affinity and a narrower molecular band gap. The introduction of position-Fixed, uniformly and densely distributed deep traps in the material effectively enhances the electrical performance of the cable insulation material. This research has certain reference value for the development of DC power cable insulation materials.