POWERGRID to convert Tamil Nadu’s single-circuit 400 kV line to quad double-circuit by 2028
POWERGRID Corporation of India Limited has approved an investment of Rs 772.65 crore for the upgradation of the Udumalpet–Madurai 400 kV Single Circuit (S/c) transmission line to a Udumalpet–Madurai 400 kV (quad) Double Circuit (D/c) transmission line in Tamil Nadu.
The investment was approved by the company’s Board of Directors at its meeting held on June 26, 2026. The project is scheduled for implementation within 30 months from the date of allocation and has a targeted completion date of August 11, 2028.
Project scope
The project involves converting the existing 400 kV single-circuit transmission line into a 400 kV quad double-circuit line to increase power transfer capacity and strengthen grid reliability in Tamil Nadu.
The existing 127 km Udumalpet–Madurai transmission line was commissioned in 1993 and has been experiencing heavy loading. According to the National Committee on Transmission (NCT), the line operates close to its surge impedance loading (SIL) limit during the peak wind generation season, with thermal loading of about 850 MVA and loading of up to 750 MW under certain operating conditions.
The project will replace an earlier proposal to reconductor the line. The conversion to a double-circuit configuration was considered feasible due to the availability of space for additional line bays at the Udumalpet and Madurai substations.
Renewable energy integration
The transmission upgrade is expected to facilitate the evacuation of additional renewable energy from Tamil Nadu and accommodate future growth in power flows across the state’s transmission network. The line, which has been in operation for more than three decades, is expected to witness higher loading as renewable energy capacity continues to expand.
The featured photograph is for representation only.
