TIRUCHY: For the first time in the city, Tamil Nadu Transmission Corporation (TANTRANSCO) has begun laying Extra High Tension (EHT) cables beneath the busy Chennai-Madurai-Tiruchy National Highway using the trenchless method - a modern technique that enables underground cable installation with minimal excavation and no disruption to traffic on major roads.
The work is part of a Rs 26.7-crore project to upgrade the 33/11 kV Mannarpuram substation into a 110/11 kV facility, aimed at meeting the city's rapidly growing power demand. The new EHT line will link the Mannarpuram and K Sathanur substations via Edamalaipatti Pudur, covering 7.4 km - with 2.4 km laid underground and 4.6 km as overhead transmission lines.
Speaking to TNIE, Mary Magdalin Princy, Superintending Engineer (SE), TANTRANSCO, Tiruchy, said the upgraded substation would help meet the increasing power requirements in key areas such as the collector camp office, the upcoming Kalaignar Library, Mannarpuram, Bharathidasan University (Khajamalai campus) and, Tiruchy airport, as part of its expansion plans.
Explaining the adoption of the trenchless method, the SE said the project had been delayed by more than two years due to permission issues with NHAI for installing transformers along the Mannarpuram roundabout. "We have now received the necessary sanctions in a diverted route circumventing the roundabout. The trenchless technology uses advanced scanners to detect underground obstructions before drilling a horizontal channel about three metres below the surface, safely below existing water pipelines," she said.
The underground stretch, which passes beneath the Chennai-Madurai-Tiruchy highway, is expected to be completed within the next three months. Meanwhile, of the 16 transformers planned along the overhead section from K Sathanur to Edamalaipatti Pudur, 14 have already been erected, with the remaining to be completed alongside the underground work. Once finished, the upgraded substation will triple the existing load capacity, enhancing supply reliability and reducing power interruptions, the officials added.