NORD.LINK
Nord.Link is one of the two planned line connections for high-voltage direct current (HVDC) transmission through the North Sea between Norway and Germany, the other is called NorGer.
The project
Statnett and TenneT are planning to build through the North Sea, a high-voltage direct current transmission system between Germany and Norway for the exchange of electrical energy. The goal is to connect the Norwegian and German power grids. For this, it is planned to be routed at 2018 a 530 km long high-voltage cable to the bottom of the North Sea. The cable is able to transmit a power of 1400 MW.
The submarine cable is to come on the Schleswig -Holstein North Sea coast at Büsum ashore. From there it is fed to the transformer station at Wilster. There, a converter station for coupling to the German high-voltage grid is built. In Norway, the cable will land in the area of Feda and directed by Tonstad in the community Sirdal. A converter station for coupling to the Norwegian high-voltage network is built.
The submarine cable will be on the Norwegian, Danish and German continental shelf in the eastern North Sea. The application for the construction and operation of the cable in the field of German Exclusive Economic Zone ( EEZ) was provided by the North Sea Cable GmbH & Co. KG from Arnhem to the responsible Federal Maritime and Hydrographic Agency ( BSH) on May 11, 2011.
An HVDC submarine cable NorNed same design with 700 MW capacity is operated in the Netherlands since 2008 between Norway and Eemshaven.
Method of Installation
The cable will be routed by a special cable laying ship on the ocean floor. A hydraulic plow thereby lifts on the seabed a trench in which the cable is buried and covered with the excavation. In areas with a stony seabed, the cable can be protected by stone sinking. The exact cable route is determined by a comprehensive mapping of the seabed along with the expected cable stretch.
Performance
The maximum possible power to be transmitted is 1400 MW and can optionally be transferred to one of the two possible directions. This performance corresponds to an average power consumption of a city of about 500,000 inhabitants, such as Oslo and Hannover. The DC power cable is operated with a bipolar supply voltage of ± 450 kV to ± 525 kV. By the bipolar embodiment, the disadvantages of a back electrode to ground in the sea, resulting in the unwanted production of chlorine compounds, and a metal corrosion of the electrodes are avoided. For at least two high-voltage cables must be laid.
Since the power supply in Germany and Norway is based on alternating current converter stations have to be built in both countries, which rectify the AC power and convert it into direct current which is transmitted through the cable. Each converter station requires an area of about 250,000 m².
Environment
Previous studies show that submarine HVDC cables have no known effects on marine animals. In the field of converter station the direct current is converted back to AC, which is then forwarded by overhead line to the nearest substation. The converter stations on land need space and make sounds similar to a substation and Umspannfelds with similar performance - but the noise level in the converter transformers is stronger due to the resulting change in the direction of harmonics. Here is the inside of the plant with 80-95 dB ( A) can be expected outside of 45 dB ( A). This is the location for the construction of the stations of importance in the election.