Diagnostics of insulation deterioration of ethylene propylene rubber using an acoustic emission technique

The aim of this study is to investigate the relationship between lowering of the insulation performance of ethylene propylene rubber (EPR) used as a covering material of a cross-linked polyethylene (XLPE) cable and partial discharges (PDs) and to establish a diagnostic technique using an acoustic emission (AE) sensor. An accelerated deterioration test was carried out and then the detected AE signals were evaluated. The results showed that not only the intensity of the AE signal but also the number of counted AE signals of more than a critical value was very useful for diagnosing the EPR. We also proposed a diagnostic sequence using an AE technique.