Sterlite Power has successfully commissioned the 400 kV double-circuit Nangalbibra-Bongaigaon transmission line, part of an interstate transmission system (ISTS) scheme. Through its special purpose vehicle (SPV) execution, the project strengthens the power infrastructure in the region, ensuring reliable electricity supply in Meghalaya. 

The project spans includes around 300 ckm of transmission lines and a greenfield substation with a 300 MW transformation capacity across the terrain of Assam and Meghalaya. It includes a 123 km, 400 kV D/C transmission line connecting Bongaigaon in Assam to a greenfield substation at Nangalbibra in Meghalaya, initially operated at 220 kV, and crossing the Brahmaputra River. 

The 220/132 kV substation at Nangalbibra, equipped with 2×160 MVA transformation capacity, also allows future expansion to 400 kV to support increasing demands. A 132 kV double-circuit transmission line (19 km) further connects Hatsinghmari in Assam to Ampati in Meghalaya for an additional power source to the region. 

The project ensures the reliable transmission of over 1 GW of power from Assam to Meghalaya. Apart from bringing the additional supply, it also decongests the downstream networks in the region, improving the quality and reliability of power supply in North-East India. Awarded through tariff-based competitive bidding in December 2021, it was completed ahead of schedule, with all necessary approvals obtained and key elements commissioned between September and November 2024.