The state-owned China Power Grid Development Co. recently awarded ABB a US$360 million contract to supply two converter stations for the 3000-W high-voltage direct current (HVDC) power link, which will transmit electricity from the Three Gorges Hydropower Plant in central China to the Guangdong province in southern China. The 940-km (585-mile) ±500-kV HVDC transmission line, the first of two 3000 MW circuits, went into commercial operation in 2004. One HVDC converter station is located at Jingzhou near the Three Gorges power plant, the other is in Huizhou near Guangzhou.

HVDC was chosen primarily because of the length of the transmission as well as the fact that the two systems are asynchronous. The photo above shows an aerial view of the Jingzhou converter station.

The Three Gorges–Guangdong ±500-kVdc Transmission Project was successfully completed and handed over to China’s State Grid Corp. for commercial operation on May 27, 2004. The client was very pleased with the early completion and performance of the project. China’s vice premier, Zeng Peiyan, formally dedicated the plant to the nation on June 6, 2004.

The Three Gorges Hydroelectric Power Plant will comprise 26 generating units—each with a rated power of 700 MW. The total generating capacity of the plant will be 18.2 GW when all units are commissioned in 2009. With the commissioning of six more units to be installed in an underground powerhouse, the total capacity of the plant will increase to 22.4 GW.

The 500-kV ac transmission lines will deliver power from this plant to Central China and Sichuan–Zhongqing Systems. Power will also be sent to East China by three HVDC lines and to South China by one HVDC line. The East China System and the South China System are asynchronous with the Central China System; therefore, the HVDC links also connect the large ac systems asynchronously.

The total capacity of this HVDC transmission system will be 10,200 MW. It will consist of the 1200 MW HVDC line Gezhouba–Shanghai commissioned in 1989 by ABB (with power generated at the Gezhouba generating station) and two 3000 MW lines. The first of these lines, Three Gorges–Changzhou, was commissioned by ABB in 2003.

In 2004, ABB was awarded the converter stations for the second 3000 MW HVDC transmission to Shanghai, which will go live in 2007. The Three Gorges- Guangdong transmission rated 3000 MW will transmit power to the South China System. l