Effect of insulation properties on the field grading of solid dielectric DC cable

The development of solid dielectric DC transmission class cable is a priority throughout much of the world to avoid risks associated with placing hydrocarbon fluids in underwater environments. However the conductivity of polymeric solid dielectrics tends to be a strong function of temperature and electric field. Based on measured material properties, we demonstrate the effect of such dependences on the field grading of DC cable for the range of measured material properties and provide an analytical approximation for computing the field of resistively graded dielectrics including the effect of temperature and field-dependent conductivity.