CHENNAI: In a significant boost to the state’s transmission network, the Tamil Nadu Power Distribution Corporation Limited (TNPDCL) on Tuesday invited bids to set up 98 new step-down substations of 33/11 kv capacity in its 12 regions, under the central government’s Revamped Distribution Sector Scheme (RDSS).
As per the policy note of the energy department for 2025-26, TNPDCL operates 789 substations of 33/11 kv capacity. Once, the 98 substations are set up, the number will increase by 12.5% to 887.
Officials said they are expecting the tenders to be decided by the end of October, and construction work to begin soon after. A senior TNPDCL official told TNIE, “We have set a target of building 133 substations across the state. Land has already been identified for 98 substations, while the process of acquiring land for the rest is still going on.”
The official said an outdoor substation of this capacity would cost `6 crore and need nearly 2,500 sq metres of land. On the other hand, the indoor substations would cost around `5 crore, with a space requirement of around 750 sq metres. “In cities like Chennai, land acquisition is a big challenge. That is why 10 out of the 98 substations will be built as indoor substations in the district,” the official added.
According to officials, Chennai (South) region will get the highest of 16 substations, followed by Tiruvannamalai (14), Villupuram (11), Chennai (North) (10), eight each in Erode, Madurai, Tirunelveli, Thanjavur and Vellore, Tiruchy (4), Karur (3), and Coimbatore (2).
He added the centre’s Rural Electrification Corporation Limited (REC) will provide financial support for the project, which is expected to cost around `600 crore.
Highlighting the need for more substations, another official said TNPDCL’s aggregate technical and commercial (AT&C) losses, which cover both transmission issues and commercial problems like illegal usage, went up from 12.92% in 2023–24 to 16% in 2024–25. As per the centre’s instructions, the losses must be brought down below 10%. “To achieve this, new substations are essential, especially in rural areas where voltage drops and line losses are higher,” the official added.