The first 660-MW unit of the Sasan UMPP was commissioned in March 2013 while the second unit was synchronised with the grid in December 2013.
"... Commercial operation has commenced at the second 660 MW unit of the 3,960 MW (6X660 MW) Sasan UMPP," the company said in a filing to the BSE.
For the third unit, boiler was commissioned earlier this month, it said.
Sasan plant is being developed by Sasan Power Ltd, a wholly-owned subsidiary of Reliance Power.