Development of 1200 KV Transmission System in India

The Indian power system is developing at an accelerated pace and it is anticipated that peak demand shall increase to over 400 GW by 2022 and beyond for which total installed generation capacity of about 500 GW is envisaged. To optimally utilize the unevenly distributed energy resources and taking into account severe right of way issues, transfer of bulk power over long distance is required. Towards this, National Grid interconnecting all the five(5) regional electrical grids comprising high capacity 400 kV/765 kV AC and ±500 kV HVDC system has been established. Today, National Grid with inter-regional capacity of about 17,000 MW is in place. Further, central grid comprising of the Northern, Western, Eastern and North-eastern Regions is operating as a single synchronous grid of 105 GW capacity and asynchronously connected to the Southern region of about 40 GW. To meet the growing power demand of various regions power transfer capacity of the inter-regional links are being enhanced continuously.

In this direction, major bulk power transmission corridors comprising of high capacity 1200kV and 765 kV AC system along with ± 800 kV, 6000 MW HVDC system are being planned. However, the 1200 kV AC system being UHV system with high Surge Impedance Loading(SIL) level, generate huge reactive power especially under light load condition which poses a major challenge of reactive power management in 1200 kV AC system under different loading conditions. Major considerations for development of 1200 kV AC system and methodologies of reactive power management to ensure secure operation of 1200 kV system are discussed in this paper.