Water treeing characterization and tree retardant compound effects in XLPE power cables

The authors describe experimentation done in establishing techniques for laboratory growth and analytical characterization of water trees. Techniques used include scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy (FTIR). Measurements of electrical properties such as capacitance, dissipation factor, and leakage current were made, but no significant differences between the virgin, field aged, and treed samples were measured. SEM and TEM techniques do indicate differences between virgin, field-aged, and vented tree cross-linked polyethylene (XLPE) samples. The FTIR technique shows that the tree retardant compound (TRC) may change the composition of the tree region. Preliminary results of characterization of virgin, field aged (without trees), and treed XLPE samples with and without treatment with the TRC are presented