Under the contracts, Amec Foster Wheeler will design and construct three 132kV overhead lines running through Ayrshire.
The company will also upgrade an existing overhead line between Kilmarnock and Coylton in Ayrshire.
The project will facilitate renewable energy supply from Scotland to England and Wales.
Work under the contracts is expected to be completed by the end of 2016.
Amec Foster Wheeler transmission and distribution business managing director Marc Boulter said: "These latest contracts confirm our position as a leading player in a growing market, the good relationship we have with long-term customer SP Energy Networks and the strength of our delivery teams."
Over the last four years, Amec supplied eight similar projects for Scottish Power, as well as signed 20 substation contracts with SP Energy Networks.
On behalf of supply companies, SP Energy Networks provides power to around 5.2 million customers throughout Great Britain.
