DolWin3
The DolWin3 project is the third offshore grid connection in the so-called DolWin cluster. The offshore grid connection connects two wind farms in the south-western part of the German North Sea with the onshore transmission grid. Around 160 kilometers of cable were laid for this purpose: 80 kilometers each at sea and on land.
The DolWin3 project is the third offshore grid connection in the so-called DolWin cluster. The offshore grid connection connects two wind farms in the south-western part of the German North Sea with the onshore transmission grid. Around 160 kilometers of cable were laid for this purpose: 80 kilometers each at sea and on land.
- DolWin3
About the project
In July 2017, the heart of the DolWin3 grid connection, the DolWin gamma converter platform, was installed at sea. The platform, built in Warnemünde, Mecklenburg-Western Pomerania, covered a six-day journey along the German and Danish coasts to its final location in the North Sea. There it was successfully installed over several days on the substructure already installed in 2016 - the so-called Jacket. The 900 megawatt grid connection is in operation since September 2018. With DolWin3, more than one million households can be supplied with clean wind energy.
Connecting concept
The electricity generated at sea is collected in the wind farm's own transformer station. From there the energy is transported to TenneT’s offshore converter platform via a 155 kilovolts three-phase alternating current (AC) cables. The conversion of AC to direct current (DC) takes place in the offshore converter station. The electricity is then transported by submarine and underground cable to the corresponding land station. Here, the electricity is converted back into AC and fed into the TenneT extra-high voltage grid.
Impressions
The voyage from the shipyard in Warnemünde along the German and Danish coasts took six days until DolWin gamma reached its destination.
The offshore platform DolWin gamma was installed right next to the offshore platform DolWin alpha.
The onshore converter station of DolWin3 is located in Dörpen/West
The converter is housed in a so-called valve hall to protect it from environmental influences.
The transformer, which weighs around 500 tons, is located in a room specially equipped for safe operation and has special corrosion protection to shield it from the harsh offshore climate.
Cable laying in the Wadden Sea is only possible in a limited time slot in summer due to environmental protection measures.
Empty tubes for the upcoming cable pull in – roughly 30 percent of the cables were laid via horizontal directional drillings.
The cables are laid out on roller conveyors before the cable is being pulled in.
