At last, the largest hydroelectric plant in the world in power generation, Itaipu Binacional, counts with power transformers manufactured by a Brazilian company. There are two transformers: the TR 256 MVA/550kV 60 Hz on the Brazilian side of the plant and the TR 275 MVA/550kV 50 Hz in Paraguay.

And it’s a double commemoration because WEG has become the first company in the world to carry out VFT - Very Fast Transient tests on transformers. This kind of test which is essential to assure that the equipment will endure all the very fast voltage oscillations during its operation has never before been carried out at the final reception of the transformer because of its complexity, risk and high cost. A Calculation Memory was provided when the original transformers were supplied to the plant.

Produced at the WEG transformer plant in Blumenau, in the state of Santa Catarina, the two power transformers of more than 200 tons each will start operation at Itaipu in the beginning of 2010 at a gas insulated substation - GIS.

“We have met with all of the customer’s requirements using the best technology in the world on the design, in the manufacturing and the direct supportability of transformers to very fast transients. We are sure we are offering an efficient and effectively safe product”, explains Francisco Rebordão, technical manager at WEG Transformadores.

WEG was appointed to supply the equipment to Itaipu in 2003 and since then has made high investments in infrastructure and technology to meet the needs of the energy sector. During the last three years the company has injected more that R$ 56 million in the Blumenau plant. Eight million reais alone were invested on the expansion of the laboratory. “To supply equipment this size to the largest hydroelectric power plant in the world proves we are ready to meet the needs of both the domestic and foreign markets”, assures Carlos Diether Prinz, Director at WEG Transformadores.

WEG and Itaipu are also partners in other innovating projects such as the Palio Weekend Elétrico developed along with Fiat.

Tests
Primeiro caso no mundo de verificação direta nos ensaios finais da verificação da suportabilidade de transformador to very fast voltage transient, typical of operations in gas insulated substations. The VFTsurges were generated by cutting the waves in the SF6 gas using the testing device specially developed by WEG for this purpose. During the tests, the technical team evaluated, among other variables, the occurrence of discharges of any nature, internal or external, and eventual perforations in the insulation. The total combination of tests for both transformers lasted approximately 2 months.

Application
The TR 275 MVA 60 Hz will be installed as replacement equipment on the Brazilian side of the plant and the TR 256 MVA 50 Hz on the Paraguayan side.

Technical data
275 MVA 50 Hz:
Total weight: 228.135 kg
Length: 6915 mm
Width: 6440 mm
Height: 7695 mm

256 MVA 60 Hz:
Total weight: 202.965 kg
Length: 6650 mm
Width: 6300 mm
Height: 7260 mm

Investments
Since 2006, WEG has already invested over R$ 56 million on infra-structure and technology on the Blumenau plant.
To meet the demand of the domestic market, the United States, Canada and Central America, WEG has invested R$30 million on the construction of a new plant of transformers in Mexico, inaugurated in April of this year.
For the Itaipu project, WEG has invested R$ 8 million on testing equipment and on the construction of a new laboratory to carry out tests on the large size transformers.