Space charge and electric field characteristics of polymeric-type MV-size DC cable joint models

Space charge and DC electric field characteristics have been investigated on medium voltage size models of cable joints composed of cross-linked polyethylene (XLPE) and ethylene-propylene rubber (EPR). The joint models were constructed in such a way that the dielectric interface between XLPE and EPR was identical to the interface encountered in pre-molded joints. Space charge measurements were performed on the joint models by means of the pulsed electroacoustic method under the same thermal conditions that actual cable joints experience in the field. Consequently, space charge dynamics was studied in the presence of a temperature gradient across the insulation of the joint model.