VolkaInfra will install 10 kilometres of underground cables from the point where the project's export cable reaches land near Rhyl, north Wales, to a new onshore substation.
The company will also link the new onshore substation to the national grid substation at Bodelwyddan, near St Asaph, also in northern wales.
VolkerInfra is a subsidiary of Dutch engineering and infrastructure group VolkerWessels.
Dong's Burbo Bank Extension was approved by the UK government in September 2014. It is the first commercial project to order the MHI-Vestas V164 8MW turbine.
The project is being installed off the UK's northwest coast in Liverpool Bay, alongside the existing 90MW Burbo Bank project, also developed by Dong.
VolkerInfra also worked on the onshore cable installation for Dong Energy's 210MW Westermost Rough and Gunfleet Sands projects in the North Sea.