Pioneering construction of an extremely high-power electrical line in Brazil

Omexom Transmission Lines in Brazil has completed the construction of a 230 kV transmission line with the country’s largest installed renewable energy capacity of 846 MW. The project featured notable technical and logistical challenges, innovative technological choices and strong CSR commitments.

Launched in June 2023 and completed in April 2024, construction of the Serra do Assuruá wind power complex in Gentio do Ouro, Brazil – 24 farms of 188 turbines, each 90 metres high – was an opportunity to implement a project on an exceptional scale. The purpose of this project 600 km from the Bahia state capital, Salvador, in north-central Brazil, was to address the increase in production flows in the region and the expansion of regional interconnectors.

Implemented by the Engie group in partnership with Omexom Transmission Lines Brazil (VINCI Energies), this remarkable project involved the construction of more than 28 km of a 230 kV transmission line with a capacity of 846 MW, markedly higher than the average power of 230 kV lines, which is approximately 400 MW. “This difference in capacity represents not only a technological advance, but also a pioneering enhancement to the country’s electrical infrastructure,” says Henrique Santos, Project Engineer at Omexom Transmission Lines Brazil.

Challenges and innovations

To meet the challenge of designing and implementing a transmission line of such high capacity, the Omexom team had to address a series of technical and logistical issues, from the selection and installation of materials to the correct sizing of structures and effective management of resources.

They also had to adapt to the unique features of the terrain in this mineral-rich region of Brazil, where it was essential to carry out special geological studies to design the electrical earth connection system. In addition, a particularly drawn-out rainy season had to be managed during the works period.

A notable example of the way in which Omexom, the VINCI Energies energy infrastructure brand, overcame these technical challenges was the tremendous effort by the engineering team to design an effective solution for managing the project’s unprecedented power levels.

“A technological advance, but also a pioneering enhancement to Brazil’s electrical infrastructure”

Henrique Santos explains: “During the budget planning phase, we realised that no 500 kV connection would be available at one of the two substations involved – namely, SE Gentio do Ouro II and SE Serra do Assuruá. We carried out a study to determine the number of cables per phase and the gauge required, using the software transient electromagnetics.”

The solution? “We installed four cables per phase, but opted for a single rather than double circuit, which was more economical in terms of the amounts of steel and concrete required for the tower structures and foundations. The latter have to be stronger to support the four cables used per phase. In total, we installed more than 395 km of cables.”

 Local resources

Another noteworthy feature of this project was Omexom’s decision to make maximum use of local resources. “The vast majority of the goods and services used in the execution phase (housing, food, internet, water, energy, civil engineering materials) were sourced from close to the project site,” says Henrique Santos. “Only the large supply orders, for example the metal structures, conductor cables and insulation, were purchased from non-local suppliers, due to their complexity.”

The management of human resources was another major challenge of this project. During the works period, 457 direct and indirect jobs were created, with a sizeable local workforce. At the project’s height, 265 workers were simultaneously present on site.

“The customer also had strict requirements on employee safety during the works, which aligned perfectly with our own employee safety focus,” says the Omexom Project Engineer. “Before beginning any activity, a pre-task meeting was organised with all the project managers and operatives to familiarise them with the security procedures.”

12/12/2024