2016 Volume 136 Issue 9 Pages 603-608
Overheating during the manufacturing process of a cross-linked polyethylene-insulated cable often induces brownish resin, which may become a starting point of breakdown and water trees. In this study, an XLPE sheet was overheated and cut to many pieces of squares with various sizes from 0.5×0.5 to 10×10 mm2. Then, each piece was sandwiched between two sheets of low-density polyethylene and its absorption intensity was measured at terahertz (THz) frequencies. Furthermore, the spatial distribution of absorption was measured in the form of a two-dimensional image by scanning the sample. As a result, it has become clear that the whole absorption increases in a range from 0.5 to 5.0 THz when the volume of overheated part becomes bigger. Moreover, the distribution of overheated parts can be visualized by the THz absorption imaging.
The transactions of the Institute of Electrical Engineers of Japan.A
The Journal of the Institute of Electrical Engineers of Japan