Assessment of Thermal Aging Degree of 10kV Cross-Linked Polyethylene Cable Based on Depolarization Current

During the long-term operation of high-voltage cross-linked polyethylene (XLPE) cables, cable will gradually deteriorate under effect various aging factors. Thermal is one key factors directly related to reliability XLPE cables. In this paper, thermal samples are prepared for PDC measurement. Based on polymer trap theory and extended Debye model, shape curve, depolarization charge, parameters factor (A), elongation at break retention rate (EB%) their relationships different degrees analyzed. The results show that current curve charge can preliminarily judge condition XLPE, but it not accurate enough. $R_{3}$ notation="LaTeX">$\tau _{3}$ branch, with largest time constant must be most sensitive aging. With increase degree, A shows an upward trend, has a nonlinear relationship EB%. Under temperature 140 °C, after 15–25 days aging, suggests in moderate severe stage, test should performed carried out cables have been used 21 years evaluate insulation condition. study reveals PDC-based serviced as effective tool prediction insulation.