Dong will use two of RXPE's Statcoms and two transformers to help support compliance with the UK grid code.
This is the second contract in recent weeks for the project. In mid-March, Dong contracted J Murphy to build the onshore substation for Race Bank.
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.