ABB was selected by Power Grid Corporation of India Ltd. to deliver the world’s first multi-terminal UHVDC transmission link. The ±800 kV North-East Agra UHVDC link will have a record 8,000 MW converter capacity, including a 2,000 MW redundancy, and transmit clean hydroelectric power from India's northeast region to the city of Agra, a distance of 1,728 km.
The link comprises four terminals in three converter stations with a 33 percent continuous overload rating, enabling an 8,000 MW conversion - the largest HVDC transmission system ever built.
ABB and Bharat Heavy Electricals Ltd. (BHEL) have turnkey responsibility for execution, including system engineering, design, supply and installation of three HVDC converter stations. Stage one is scheduled to be operational in 2014-2015, stage two in 2015-2016.
Northeast India has abundant untapped hydropower resources scattered over a large area, but load centers are hundreds or even thousands of kilometers away. Power must pass through the so called "chicken neck area," a very narrow patch of land (22 km width x 18 km of length) in the state of West Bengal having borders with Nepal on one side and Bangladesh on the other side.
One converter station will be in the northeastern state of Assam, and a second in the state of West Bengal in eastern India. The other end of the DC line will terminate at Agra, where two bipolar converters will be connected in parallel. The 800 kV equipment yard at Agra will for the first time be placed indoors.
This is the second ABB-built multi-terminal HVDC link. In 1990-1992, a large-scale three terminal transmission link was constructed in North America called the Québec - New England HVDC Transmission - the first of its kind in the world.
At full capacity, the North-East Agra UHVDC link will be able to supply enough electricity to serve 90 million people based on average national consumption. Ultrahigh voltage minimizes transmission losses and improves grid efficiency.