Applications of underground transmission lines for high power AC transmission

Applications of gas-insulated transmission line (GIL) has increased in applied length and required power. World-wide underground bulk power transmission is getting more and more imported due to restricted available space and higher concentration of electric load mainly in metropoles and large cities. The increase of required electric power at concentrated locations requires power transmission solutions which allow maximum use of the available space. GIL is one technical solution which offers both requirements: highest power transmission and smallest space requirement. An outlook is given about the improvements of the laying process by using the concept of a mobile factory. In this paper a short overview of recently executed project by Siemens AG is given to give information about typical technical layouts and data. The chosen project can be seen as future references in application of GIL.