Electric Field and Current Density in the Insulation of High Voltage Cables Taking Into Account its Nonlinear Properties

The features of electric field disturbance and current density increasing in cross-linked polyethylene (XLPE) insulation of high voltage power cables were studied with taking into account the presence of water microinclusions and water trees in such insulation during operation. Also, there were taking into account nonlinear insulation properties, in particular increase in a specific electrical conductivity in local areas of the dielectric with the highest strength of the electric field. The paper defines the patterns of change in the magnitude of the electric field stress and total current density in the XLPE insulation near water microdefects and the additional impact on such patterns the electrical conductivity dependence of field strength in local volumes. It is indicated that such electrophysical effects on polymer insulation led to an increase in the density of the leakage current, losses, local overheating and destruction of the insulation and should be taking into account.