1200 kV single( energized May 2012) and double circuit suspension towers( energized October 2012). Single circuit tower requires right of way of 89 m.
India’ s sprawling transmission grid consists of some 95,000 circuit-km of 400 kV( mainly) and 765 kV lines as well about 125,000 circuit-km of lines operating at 220 kV. In addition, there is a DC system comprising around 7500 km of ± 500 kV lines. Vast as that system is, however, it cannot cope with the lofty projections for incremental power throughput required to meet economic development targets over the coming decade.
Phots: Courtesy Alberto Pigini
For example, based on estimated average GDP growth in coming years, peak demand is expected to increase from the present 168 GW to 250 GW in 2017 and then to 372 GW by 2022. To transport the additional power needed under such a scenario, the existing number of transmission corridors would have to be significantly increased. But in the case of India, with limited land availability, growing ecological advocacy and many landowners, this would prove a formidable if not impossible challenge.
It was these types of considerations that drove planners at India’ s PowerGrid to look toward UHV as the only realistic alternative to meet the country’ s future electricity requirements by making maximum use of existing or slightly expanded power corridors.
All diagrams: Courtesy PowerGrid of India
While 1200 kV may seem as breaking new ground, the first application of such a system voltage was actually tested and commissioned almost 30 years ago in the former Soviet Union. Even before that, Japan had energized a limited 1000 kV system while researchers in Italy also developed and tested equipment for such a system. China started R & D on its own 1100 kV network in 2005 and a 650 km pilot project was launched in early 2009 that is the basis for additional lines now on the drawing boards or already under construction( see INMR Q1 2010 & Q4, 2012).
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