电力工程技术 (Jul 2022)

Aging assessment of XLPE based on high temperature dielectric spectra

  • DENG Honglei,
  • YANG Hao,
  • XIE Yue,
  • LIU Gang,
  • ZHAO Yifeng,
  • FAN Xinghui

DOI
https://doi.org/10.12158/j.2096-3203.2022.04.020
Journal volume & issue
Vol. 41, no. 4
pp. 156 – 161,219

Abstract

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To study the changes in dielectric properties for thermally aged cross-linked polyethylene (XLPE) at different temperatures, the pure thermal and thermal-radiation aging tests are done. Thermal aging is carried at 80℃, 100℃, 135℃ and 155℃, lasting for 100 to 800 hours. The same conditions combined with 100 Gy/h gamma rays are done for thermal-radiation aged samples, and the dielectric spectra are measured from 25 to 200℃. The results show that the activation energy and values of β decrease obviously after the introduction of rays. At the same aging temperature and radiation conditions, electrical conductivity and relaxation peak frequency increase as the increasing aging time, which is a good reflection of dielectric properties during the aging process. Under different temperatures, the deviation in complex permittivity and modulus at lower frequency becomes more distinct compared with the values at a higher frequency. Finally, the dielectric properties under high temperature and low frequency could be a good indicator for the evaluation of XLPE degradation.

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