HVDC gains in popularity
High Voltage Direct Current (HVDC) transmission lines are increasing in popularity. They mean lower losses than AC over long distances while individual grids are easier to connect together because there is no need to synchronise phasing.
It is feasible, given time, that HVDC grids could encircle the globe and provide electricity to under-developed regions. It also means the world will need fewer central power stations because, during the night, when most generators run down, the facility could be fully used to supply adjacent countries that are still in daytime.
Now, Siemens Power Transmission and Distribution and consortium partner Bharat Heavy Electricals Ltd have been awarded an order by the Power Grid Corporation of India to construct a 780km (485 mile) HVDC transmission line between the provinces of Uttar Pradesh and Rajasthan.
The purpose of the new HVDC transmission system is to strengthen the power supply to the growing region around the megacity of New Delhi without the need to build additional power plants. The order has a total value of approximately 235 million financed by World Bank, with Siemens' share amounting to about 170 million. Final commissioning is scheduled for November 2009.
The planned project is the fourth long-distance HVDC transmission link in India and will have the highest power rating of all. In comparison to a conventional 400kV AC transmission line this link improves energy efficiency so that 688,000 tons of CO2 will be saved.
Siemens also supplied the second longest HVDC transmission link in the world, which runs over 1450km from the state of Orissa in the east of India to the industrial region around Bangalore in the south.
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