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India’s PowerGrid beats global peers in high-voltage game

 India's PowerGrid and a clutch of 35 domestic electrical equipment manufacturers have jointly developed a system for transmitting bulk power with a force of 1,200 kV (kilo volts), beating members of an elite club of 5-6 economies in the high-voltage transmission technology game.

To put things in perspective, the new system's transmission force is 5,454 times more than that of domestic power supply and 48 times more than the voltage - 25 kV, or 25,000 volts - at which electricity is supplied to locomotives through overhead wires.

Ratings of 1,000 kV and above qualify as 'ultra-high voltage (UHV)' and UHVAC (ultra-high voltage alternate current) systems allow more power to be pushed through a line to make more efficient use of infrastructure and reduce costs. Globally, most of the transmission networks are rated at 400-800 kV, described as 'high voltage'.

Russia, Japan, Italy, US and China have dallied with UHVAC lines but with 1100 kV ratings.

"Our UHVAC system is completely 'made in India'. Its carrying capacity is 6,000 MW per circuit (line). This is equivalent to 10-12 circuits of 400kV or 2-3 circuits of 800kV AC lines. Adoption of 1200kV transmission system with nominal voltage of 1150 kV allows 20% to 30% additional capacity compared to nominal voltage of 1,000 kV adopted by other countries," PowerGrid chairman Indu Shekhar Jha told TOI .

Two lines connecting PowerGrid's national UHVAC testing station between Bina in Madhya Pradesh and Wardha in Maharashtra have been successfully reconfigured to 1,200 kV rating using equipment manufactured by Bhel, CGL and Indian arms of ABB, Toshiba, Siemens and Crompton Greaves, among others. The first commercial UHVAC line is coming up between Satna and Wardha, covering a distance of 400 km.

"The testing station is unique venture in terms of the number of players coming together on one platform. The station will give confidence more Indian equipment manufacturers to get into UHVAC segment, creating a domestic ecosystem. Indian industry is now in the elite club of UHVAC equipment manufacturers owing to this test station," Jha said.

The testing station has drawn the attention of utilities across the world who are seeking inputs for developing international standards for UHVAC transmission systems.

Transmission bottleneck has long been considered the Achilles' heel of India's power sector. As TOI reported on July 5, 2015, more than 3 billion units of power - roughly a day's national consumption - was lost in 2014-15 due to congestion in transmission system. The figure has since come down drastically as PowerGrid has switched on several new lines.

But more connectivity has to be built rapidly for the 175 GW (giga watt) renewable capacity that the government is putting in place. But getting RoW ('right of way' or permission for placing towers on state or farm land) has often come up as a speed breaker. The UHVAC system would help overcome this hurdle by using existing RoWs to lay lines with higher capacity.