This study focused on the effect of pre-crosslinking on the electrical properties of XLPE insulation for HVDC cables. The XLPE samples were pre-crosslinked at 140, 150 and 160◦ C. The space charge and DC breakdown characteristics of the XLPE samples with and without pre-crosslinking were investigated. The results show that the pre-crosslinked XLPE samples have an obvious space charge injection and transportation, resulting in more severe electric field distortion. Under the electric field of 100 kV/mm, the electric field distortion rates of the XLPE samples pre-crosslinked at 150 and 160◦ C reached 51% and 72% respectively, which were much higher than that of the XLPE sample without pre-crosslinking (14%.) Compared with the XLPE without pre-crosslinking, the breakdown strengths of XLPE pre-crosslinked at 140, 150 and 160◦ C were reduced by 11%, 6% and 7% respectively, at the temperature of 50◦ C. It is concluded that the pre-crosslinking leads to imperfect crystallization and micro-defects in the amorphous region of XLPE, thereby leading to more space charge accumulation and reduced DC breakdown. The pre-crosslinking of XLPE insulation therefore should be prevented during HVDC cable manufacturing.
CITATION STYLE
Zhang, Z., Wu, Y., Fu, C., Meng, S., Peng, C., Li, Z., & Du, B. (2022). Effects of Pre-Crosslinking on Space Charge and Breakdown Characteristics of XLPE Cable Insulation. Energies, 15(7). https://doi.org/10.3390/en15072360
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