Power Grid Corporation of India Limited (POWERGRID), a Maharatna CPSU under Ministry of Power has upgraded Assam’s New Mariani Sub-station from 220 kiloVolt (kV) switching station to a 400/220 kV Sub-station with 2×500 MegaVolt Ampere (MVA) transformation capacity, 2×125 Mega volt ampere (re- active) power compensation along with other associated bays under North Eastern Region Strengthening Scheme (NERSS-VI) project.
In March 2013, the New Mariani Sub-station had been commissioned in Jorhat District with 20 MVAR reac- tive power compensation capacity. With this upgradation, connectivity at 400 kV voltage level between 400 kV Misa Sub-station, 400 kV New Mariani Sub-station & 400 kV Kohima Sub-station has been established. It has now become the first 400 kV Sub-station of upper Assam, which will serve as a key station for catering to augmentation of power in upper Assam, Nagaland, Manipur and the entire North Eastern Region. This capacity addition will add efficiency and robustness, leading to supply of reliable power.
The project has been commissioned timely despite limitations in wake of COVID-19 pandemic, difficult soil and weather conditions. The bays & additional 400 kV D/C line section for upgradation of Misa-New Mariani line from 220 kV to 400 kV level are now under commercial operation. The project has been commissioned as part of “Azadi Ka Amrit Mahotsav” marking 75 years of India’s Independence.
POWERGRID presently has 264 Sub-stations and 172,104 ckm and 464,292 MVA of transformation capacity. With the adoption of latest technological tools and techniques, enhanced use of automation and digital solutions, POWERGRID has been able to maintain average transmission system availability >99%.