The IE Madeira consortium has awarded a 20 million euro contract for overhead lines for the world’s longest power transmission link, Brazil’s Madeira River Power Interconnection.

This new HVDC (high voltage direct current) link, the first of two, will transmit 3,150MW of power produced by the Rondônia hydroelectric plant in northwest Brazil to São Paulo, Brazil’s main economic center, over a distance of 2,375 km. HVDC transmission at 600 kV is being used to minimize transmission losses over the long distance and the link will eventually comprise two parallel overhead lines. Nexans has been selected to provide the conductors for the first circuit by IE Madeira, a consortium comprising the utilities Furnas, Chesf and CTEEP.

The Madeira River Power Interconnection is a bipole circuit, with each pole comprising four overhead conductors. Overall, Nexans is supplying some 6,700 km – equivalent to 21,120 tons – of its All-Aluminium Conductor (AAC) for the project. Each conductor features 91 bare wires, with a diameter of 44.4 mm.

A bespoke cross-section has been developed specifically for the Madeira River Interconnection project to provide the desired electrical and mechanical properties (breaking stress, elongation, linear thermal expansion coefficient for example) by taking into account the line's construction conditions, such as topography and climate. The typical span between the towers will be 500 meters.

To ensure the total safety and effectiveness of the Nexans solution, an extensive evaluation program, including creep, stress and stretch tests, among many others, was conducted in close consultation with IE Madeira.

The cable is being manufactured at three Nexans plants in Brazil, located in Americana (São Paulo State), Lorena (São Paulo State) and Rio de Janeiro (Rio de Janeiro State). The first transmission line is scheduled for installation in the last quarter of 2011, while the entire project should come on line by 2013.

The Madeira River Interconnection will set a new record as the world’s longest power transmission link, with a route length of 2,375 km across five states in Brazil and 86 towns and cities. The current record for an operational HVDC project is also in Brazil – the 900 km line from Itaipu Dam to Ibiuna in São Paulo State. The overall world record is for the 1,700 km AC (alternating current) line between Inga and Saba in Zaire.