Research on Electrical Properties of XLPE HVDC Cable Insulation Materials Based on Nanocomposites

Abstract

In order to develop Chinese self-own high voltage direct current (HVDC) cable insulation materials, three kinds of low-density polyethylene (LDPE) from Chinese petrochemical manufacturers were selected as the polymeric matrix. The conductivity and breakdown strength of the three kinds of polyethylene were tested at different temperatures to select the one with the best performance as the insulating base material. Then the modified nanoparticles were added to the LDPE and performed strong shear mixing in a twin-screw extruder to obtain a DC cable masterbatch with a mass fraction of 10%. Then the masterbatch was mixed with the base material in a ratio of 1:10, with adding a certain amount of additives to obtain Chinese DC cable material. The SEM observation of the cable material showed that the nanoparticles had good dispersibility. Test pieces made from the cable materials were then prepared for electrical performance tests, which showed that the performance of the Chinese material was better than that of the imported material. Model cables with an insulation thickness of 5.5mm were produced using Chinese and imported materials. However, the DC breakdown voltage test showed that the imported material was better than the Chinese materials. The results indicate that it is not enough to study the development of DC cable materials from the test piece level, but also needs to carry out more tests and studies at the cable level in combination with the actual production process.