The Xiangjiaba central which belongs to the China Three Gorges Corporation (CTG) is equipped with 800 MW Francis turbines and generators of 889 MVA each, the most powerful built to date. Each unit has a maximum power output equivalent to a small nuclear power plant. Once completed, the plant will have a total capacity of 6400 MW of renewable energy.
Signed in the fall of 2008, the Xiangjiaba contract involved the design, development, manufacture and control of the installation and commissioning of four Francis turbine generator of 800 MW.
Production units supplied by Alstom incorporate many unique innovations. The wheels feature a diameter of nearly 10 meters and weigh over 400 tons, according to Alstom have “Advanced hydraulic design guarantees a behavior of the machine very fluid, even in areas difficult to exploit.”
In order to obtain an optimal design of such a power generator, Alstom has provided the first stator windings of 23 kV air-cooled “These coils involve raw materials of high quality and a high dimensional accuracy during manufacture. Until recently, only one central operating at such a voltage, with windings supplied by Alstom, but with a cooling water flowing in the stator windings in order to remove the heat during the generation of electricity. ”
A Xiangjiaba, the challenge was to develop 23KV windings are cooled by air circulation, which require less auxiliary equipment, space and maintenance.
Extensive research in the field of ventilation and stator windings, as well as extensive testing on the stator bars were used to validate the design of the generator. Testing commissioning, as well as the recent connection to the network is the latest evidence of this technological breakthrough in the design of rotating electrical machines of large size.
This project is part of a successful cooperation between Alstom and China Three Gorges Corporation (CTGPC), which also includes deliveries to Central Three Gorges Left Bank, the Central Three Gorges Right Bank and the underground powerhouse of the Three Gorges.