Investigation of aging effects in cross-linked polyethylene insulated cable using terahertz waves

A method to detect the degree of aging in cross-linked polyethylene (XLPE) insulated cables, using terahertz (THz) waves, is reported in this letter. With increased aging time, the real permittivity decreases in the frequency range from 0.7 to 2.5 THz. The imaginary permittivity and absorption coefficient of unaged XLPE sample are larger than those of thermally aged XLPE insulated cables. These findings indicate that the aging degree of XLPE can be obtained by measuring its permittivity and absorption coefficient by THz waves.