Frequency domain dielectric relaxation in water tree degraded XLPE cables

Water tree degradation is a potentially fatal form of degradation for medium voltage XLPE distribution cables. As such it is important that distribution companies can assess the condition of their underground cable network, with respect to this form of degradation, in order to be able to develop effective and efficient maintenance strategies. Frequency domain dielectric spectroscopy can be used to non-destructively assess cables with respect to water tree degradation. This paper will review the progress made on this task by the authors over the last 2 years, including innovative work on the development of a diagnostic criterion, dielectric modeling and the practical application of dielectric response theory.