Contractor Carillion is laying 47 kilometres of underground cable between Weybourne on the north Norfolk coast to Necton. There they will connect to the substations.
According to the project's developers, it will be the longest onshore underground cables for a UK wind project. It is expected to be completed by early 2016.
The two substations are being built by Siemens. Completion is set for April 2016 with testing set to go on until November.
Dudgeon is being developed by Statoil, Statkraft and Masdar. The project will use Siemens 6MW turbines.