JDR Cables will supply 66kV inter-array and export cables to the 24MW floating array set for a site off north-west Portugal.
The UK firm said the contract also includes the first application of its "dynamic cabling" for floating offshore wind.
"JDR has an extensive track record in the design and supply of dynamic products to the oil and gas industry. This experience was essential in designing and optimising the cable configuration and accessories to meet the needs of this floating offshore wind project," said JDR chief technology officer James Young.
The cable firm said it also designed a cable break away system used to pro
Portugal's economic ministry gave the go-ahead to the project in December, following a four-year 2MW prototype campaign between 2012 and 2016.
The new project will see three MHI Vestas V164-8.0MW turbines installed at the site in 2019, subject to a final investment decision.
Windplus is a consortium comprising EDP Renewables, Mistubishi, Chiyoda, Engie and Repsol. The ballasted triangular semi-submersible foundation was designed by Principle Power.