PGCIL to upgrade critical lines in Tamil Nadu under Rs.1,800-crore RTM project

T&D News

T&D India
February 11, 2026

Power Grid Corporation of India Ltd (PGCIL) has been assigned two projects, under the regulated tariff mechanism (RTM) framework, for upgrade of two critical lines in Tamil Nadu. The total estimated outlay is over Rs.1,800 crore.

Both these projects were recommended during a recent meeting of the National Committee on Transmission (NCT).

S/C to D/C (quad)

The first project involves the 400kV single-circuit Udumalpet – Madurai line, which was commissioned in 1993 and is currently experiencing heavy loading. This line, running around 127 km, will be converted into a double-circuit (quad) line with capital outlay of Rs.643 crore. The project is scheduled for commissioning in 30 months.

NCT was informed that the Udumalpet – Madurai line is operating very close to its SIL (surge impedance loading) limit during peak wind demand season. The thermal loading of the line is about 850 MVA and under certain scenarios, maximum loading of 750 MW has been observed on the line.

In view of space available for additional line bays at the Udumalpet and Madurai substations, it was decided to convert this line into a double-circuit line, discontinuing the earlier proposal of reconductoring.

Part of PGCIL’s network, this line has completed 32 years of operation and is expected to witness greater loading as more RE generation from Tamil Nadu is integrated in the grid.

Reconductoring

The second project involves reconductoring with HTLS conductor (capacity: 2,100MVA) of two 400kV double-circuit lines. The two lines are Tirunelveli-Udumalpet line (around 265 km) and the Pugalur-Madurai line (around 124 km). The aggregate project cost is estimated at Rs.1,193.50 crore with a completion timeframe of 24 months. The project will also involve upgrade of bay elements at the Tirunelvi, Udumalpet, Pugalur and Madurai ends of the two lines.

Like the Udumalpet-Madurai line case discussed earlier, the two lines are also subject to heavy loading. The situation will exacerbate with higher RE generation envisaged in Tamil apart from generation from the upcoming Unit-3 and Unit-4 (2×1000-MW) of the Kudankulam atomic power station of Nuclear Power Corporation of India Ltd (NPCIL). The latter is coming up through an ISTS-TBCB scheme housed under “Powergrid Kudankulam Transmission Ltd” currently under execution, and scheduled to commission by July 2027.

PGCIL’s RTM work-in-hand

As of December 31, 2025, PGCIL had outstanding work-in-hand worth Rs.1,45,513 crore. Of this ongoing RTM projects accounted for 6.8 per cent (or Rs.9,934 crore) while new RTM projects had a share of 16.2 per cent (or Rs.23608 crore). Dominating the proceedings was the TBCB projects segment with a share of 75.4 cent (or Rs.1,09,767 crore).