Development of failure prediction method for accessories of XLPE cable lines

Since dielectric breakdown failures have sometimes occurred in XLPE (cross-linked polyethylene) cable facilities, the development of a failure prediction method is strongly desirable so that such failures during power transmission can be prevented in advance. As a result of failure analysis of 77 kV class XLPE cables, it has been found that most of such dielectric breakdowns in power transmission lines have occurred in the accessories, caused by defective execution. The authors have succeeded in developing a method to detect partial discharge occurring before the accessories generate such dielectric breakdown. They describe this method, and report on a study to apply it to failure prediction technology. The authors constructed a line incorporating various types of accessories and evaluated the possibility of detecting such partial discharges to determine the practical feasibility of the proposed method. As a result, it was ascertained that one can detect a partial discharge in the case of every accessory investigated in the present study