Assessment of changes produced by thermal and electrical ageing of model LDPE cables using diagnostic dielectric tests

Experiments have been performed to assess the condition of low-density polyethylene (LDPE) cables subjected to accelerated electrical and thermal ageing at elevated temperatures. Changes in the condition of the cables have been monitored using both low frequency techniques and techniques applicable to measurements up to a few giga-Hertz. Comparisons are made between cables that have undergone accelerated thermal ageing and a combination of accelerated thermal and electrical ageing. The results obtained are discussed in terms of the ageing processes.