Influence of crosslinking condition on high-field dielectric property of electron beam irradiated crosslinked polyethylene film

In order to investigate the influence of crosslinking on high field dielectric properties of crosslinked polyethylene, the observations of high-field AC dissipation current waveforms of electron beam (EB) irradiated crosslinked polyethylene (IR-XLPE) films at 90°C were carried out by using samples with different gel fractions. The results show that the dielectric properties at 90°C depend on the position of the film from the EB irradiation side. It might be indicated that mobile carriers in the high temperature region are strongly affected not only by the electric field and/or temperature but also by the gel fraction of IR-XLPE films. In this paper, in order to investigate the space charge effect under an alternative electric field, AC dissipation current waveforms under the superposition of AC and DC electric field were observed by using IR-XLPE films with different gel fractions. The dissipation current waveforms of the 20th, 30th and 40th samples from the electron beam irradiation side (denoted here after sample No.20, No.30 and No.40) are strongly affected by the DC component of applied voltage, such as the polarity and the magnitude of the DC component of the superposition of AC and DC voltage