On the Design of Accessories for HVDC Cables: Complexity of the Field Distribution

With progresses achieved in power converter technologies, HVDC is becoming now a mature technology for energy transmission. Cable systems and cable accessories constitute important parts of the transmission systems. The question of optimal design of these systems is still a complicated issue as the field distribution is intimately linked to the electrical conductivity of insulating materials, which is indeed a substantially variable property according to temperature, field and considered material. In this work, we consider the association of different materials constituting accessories and compute the field distribution in a non-stationary state. We show that there are indeed solutions to smooth the field, but defining the right properties of the joint material is still not an easy task as it depends on the electrical and thermal service conditions.