Wikipedia
The Kontek HVDC is a long, monopolar 400 kV high-voltage direct current cable between Germany and the Danish island Zealand. Its name comes from " continent" and the name of the former Danish power transmission company "Elkraft", which operated the power grid on the Danish islands Lolland, Falster and Zealand and had the abbreviation "ek". As of today, the cable is operated by Energinet.dk in Denmark and 50Hertz Transmission GmbH in Germany.
Kontek is remarkable because, in contrast to similar facilities like Baltic Cable and Konti-Skan, all land sections of the onshore lines on Falster, Sealand and Germany are implemented as underground cable. This unusual measure, which raised the construction costs of Kontek significantly, was made for practical rather than technical reasons. Obtaining permission for building overhead cables can take a long time, and hence underground cables were used in order to ensure it was completed on schedule.