The substation will be built in east England, 15 kilometres from Kings Lynn. It will be located beside the National Grid substation at Walpole.
Dong's new substation will collect the power from the project, 27 kilometres from the UK's east coast, and connect it to the UK's grid.
A final investment decision is yet to be made on the project, but a Dong spokesperson said an announcement is expected later this year.
The project will consist of up to 91 turbines, meaning an expected turbine capacity of approximately 6MW.
Today's news joins a string of recent contract announcements over the past three months.
Seaway Heavy Lifting was handed three substation transportation and installation contracts by Dong in January, including one for the Race Bank project.