The Kontek HVDC Interconnection between Denmark and Germany has a capacity of 600 MW at 400 kV DC, and is the second international interconnection on Denmark's largest and most populous island, Zealand.
The chance to better utilize highly efficient thermal power generating units operating in Zealand and the environmental benefits of low NOx and SOx emissions from these units were strong motivations to build the interconnection. The connected areas also gain from increased security of operations and expanded power exchange and trading capability.
In June 1991, ELKRAFT, the Danish utility company on Zealand, and the production and transmission company VEAG in Germany signed an agreement to establish the interconnection. In December 1995, ABB turned the Kontek Interconnection over to the owners, SEAS (now Energinet.dk) of Denmark and VEAG (now 50Hertz) of Germany.
Even before that, the Kontek Interconnection proved a vital link in the security of Zealand`s power supply when, in late October 1995, a ship's anchor damaged the 400 kV AC power transmission cable between Sweden and Denmark. The interconnection is a monopolar HVDC transmission between the Bjaeverskov converter station about 50 km south of Copenhagen, Denmark and the German station at Bentwisch, about 10 km south of Rostock, connecting power grids in each country.
An HVDC transmission was selected because of the necessity of a sea crossing, and the fact that the interconnected grids are not synchronous. ABB won the contract for the two converter stations, and NKT Cables was awarded the contract for the 170-km cable for the Interconnection.
In 2014, ABB was awarded an order to upgrade the control and protection system, MACH. Included in the order were also operator work stations, training and spare parts. The upgrade is scheduled to go in operation in 2016.