water tree

Effect of water trees ′string of pearls′ configuration on the distribution of electric field, current and stressed volume in XLPE insulation

The processes originating in local areas of cross-linked polyethylene (XLPE) insulation of extra-high voltage cables during water tree germination between closely disposed water micro-inclusions in insulation have been studied. According to current experimental data, water trees in XLPE have not solid cylindrical shape, as it was thought previously, but they consist of closely spaced nanoscale inclusions of spheroid form and nanoscale thin water channels between them (so-called "string of pearls" confi­guration).

Interrelated processes of local electric field amplification in solid dielectrics, contributing to their degradation

The complex processes of local disturbance of an electric field, as well as the amplification of electrical strength and mechanical and thermal intensities in the solid dielectric, depending on the configuration of its conducting micro-inclusions are described.