One Nation - One Grid - One Frequency

Initially, to start the integration of regional grids leading to formation of a National Grid, the regional grids were interconnected through HVDC links for controlled power flow. The first Inter-Regional AC link (220 kV) was established between Eastern Region (ER)-North Eastern Region (NER) in 1992.

The large scale grid integration started in 2003 with establishment of 400 kV Rourkela-Raipur Double circuit (D/c) line, interconnecting Eastern Region-Western Region.

The synchronous National Grid was established in 2013 after commissioning of 765 kV Solapur - Raichur lines, interconnecting Western Region (WR)-Southern Region (SR), fulfilling "One Nation-One Grid-One Frequency". In January 2019, the 220kV Srinagar-Leh Transmission System was commissioned which connected the remote Leh region to the Nation Grid.