Evolution of National Grid:

• Grid management on regional basis started in sixties.

• Initially, State grids were inter-connected to form regional grid and India was demarcated into 5 regions namely Northern, Eastern, Western, North Eastern and Southern region.

• In October 1991 North Eastern and Eastern grids were connected.

• In March 2003 WR and ER-NER were interconnected .

• August 2006 North and East grids were interconnected thereby 4 regional grids Northern, Eastern, Western and North Eastern grids are synchronously connected forming central grid operating at one frequency.

• On 31stDecember 2013, Southern Region was connected to Central Grid in Synchronous mode with the commissioning of 765kV Raichur-Solapur Transmission line thereby achieving 'ONE NATION'-'ONE GRID'- 'ONE FREQUENCY'.