On December 7, the ±600kV Converter Valve Renovation Project for Valve Hall 4 in Phase I of the Itaipu Project in Brazil, undertaken by NARI, was successfully put into operation.
The Itaipu HVDC transmission project was completed in the 1980s. With a line length of approximately 800 kilometers and a transmission capacity of 6,300 megawatts, it is a benchmark project for extra-high-voltage and large-capacity HVDC transmission and holds an iconic position in the history of the development of HVDC transmission in the world. This renovation is the first large-scale renovation and upgrade since the Itaipu Project was put into operation 40 years ago, adopting Chinese technologies and products.
In Phase I of the renovation, the production, testing, shipment and on-site renovation of the converter valves and valve control systems for Valve Hall 4 of Pole 1 was required to be completed within 12 months. The converter valves had to make use of the original foundation of the valve hall and valve tower, and the valve control systems had to complete the interfaces with the original control and protection systems in the station.
After 40 years of operation, various drawing materials in the station had been lost over the years, and the design situations of both software and hardware were unclear, so the design of the converter valve system faced huge challenges. NARI organized teams to go to Brazil to carry out relevant work on many occasions. According to the design of the valve hall and the layout of various primary equipment, it pioneered a brand-new vertical valve tower with the structure of "external support + internal suspension". The size of the valve tower was reduced by 30% compared with the typical structure, successfully overcoming the size limitations of the Itaipu valve tower renovation. For the first time, the converter valve system of NARI achieved cross-era cooperation with the "40-year-old" control and protection system, breathing "new life" into the old HVDC transmission system.
During the project implementation period, other valve halls and AC/DC equipment in the station were all in operation with power on. The project team comprehensively and meticulously prepared various documents, coordinated all work fronts in an integrated manner, actively cooperated with the complicated management regulations in the station, and maintained high work efficiency. The original control and protection equipment belonged to the operation equipment under the control of the Brazilian side as the owner. The project team closely discussed the access schemes and testing details with the Brazilian side and carried out scheme verification in advance according to the owner's operation and maintenance plan. All access testing items were passed at one time.
