Dielectric Properties and beta-Relaxation in Cross- linked Polyethylene: Effect of Thermal Aging

Y Kemari , G. Teyssedre (1) , A Mekhaldi , M Teguar

1 LAPLACE-DSF - Diélectriques Solides et Fiabilité

The present paper aims at investigating the influence of thermal aging on the crystallinity, the permittivity and -relaxation of cross-linked polyethylene (XLPE) used in power cables. For this, accelerated thermal aging is performed on circular XLPE samples for 5040 h (210 days) at 80, 100 and 120 °C and for 1512 h (63 days) at 140 °C. Changes in the crystallinity of XLPE are assessed by Differential Scanning Calorimetry (DSC). Frequency domain dielectric spectroscopy is used to analyze the variations of real and imaginary parts of the permittivity, before and after aging. Moreover, -relaxation is investigated through loss factor ( r ") analysis in the temperature range from 0 to 100 °C at several different frequencies 10, 10 2 , 10 3 and 10 4 Hz. We show that dielectric spectroscopy is not the best suite method to reveal the earlier steps of aging.

Mots clés: cross-linked polyethylene; dielectric relaxation; thermal aging; differential scanning calorimetry; permittivity

Domaines: Sciences de l'ingénieur [physics]

Y Kemari, G. Teyssedre, A Mekhaldi, M Teguar. Dielectric Properties and beta-Relaxation in Cross- linked Polyethylene: Effect of Thermal Aging. IEEE Internat. Conf. on Dielectrics (ICD), Valencia, Spain, 5-9 July 2020., Jul 2020, Valencia, Spain. pp. 73-76. ⟨hal-03003240⟩