Underground High-Power Transmission Part I: AC and DC Transmission Techniques

In Part I and II of this paper the results of the study "Electric High-Power Transmission and Distribution in Densely Populated Areas" related to future electric underground transmission are presented. The study was conducted in the Federal Republic of Germany in the period 1973 through 1977 as a joint venture by about 100 experts of utilities, manufacturers, research centres and technical universities. Part I presents the technical and economic data of conventional and in particular of future, partly non-conventional AC and DC underground transmission techniques - such as cables with forced external or internal water cooling, SF6 insulated pipes, superconducting cables. Furthermore technical and economic data for substations - transformers, switchgear, converter stations - are given.