Work under the contract, one of the largest signed by Winder Power to date, will begin later this year and continue until 2018.
Winder will undertake the work at its 80,000 square foot factory in Leeds and on-site in Felixstowe. It will design, manufacture and install the package substations.
Winder Power group managing director Laurence MacKenzie said: "This project is one of the largest that Winder Power has undertaken in over 100 years of existence.
"A team of experienced engineers, led by our operations director Andy Pinkney and projects manager Dean Sumner, will be in the factory and on-site for approximately three years to ensure the successful completion of the project."
Winder designs and manufactures electricity transformers of up to 60 Megavolt Amperes (MVA), each with a capacity to supply electricity to around 30,000 homes.
