Main Principles of HVDC Extruded Cable Design

This chapter illustrates, in detail, the basics of HVDC extruded cable design. It presents a detailed analysis of the differences between HVAC and HVDC cables. The chapter also presents a detailed analysis of the DC electric field distribution in the typical transient conditions encountered during the service of an HVDC cable. It discusses the influence of the laying environment temperature on the steady field of an HVDC extruded cable and the effects of impulses superimposed to the DC voltage, which gives rise to a novel statistical approach to the selection of impulse voltage test levels for HVDC extruded cables. The chapter presents an overview of the problems involved by the modification of the stress distribution by trapped space charge effects. It reviews the polyethylene-based dielectrics for designing and manufacturing HVDC extruded cables, and morphology of polyethylene from the viewpoint of its influence on the performances of HVDC cable insulation.