The works related to shifting and modification of Overhead Extra High Tension (EHT-132kV & above) lines under Gujarat Energy Transmission Corporation Limited (GETCO), infringing with Mumbai–Ahmedabad High Speed Rail (MAHSR) corridor are in advance stages and 80% of the foundations and more than one third of the relocation work is already completed.
NHSRCL is relocating more than 1600 electrical transmission lines out of which 164 are overhead EHT lines and 131 nos. of Overhead EHT Lines infringements with MAHSR corridor are in Gujarat state as about 75% of the MAHSR alignment will pass through Gujarat.
- Normally the height of Transmission Lines from the ground level is in the range of 6-9 Meters, in case of National Highways Crossing it is in the range of 8-11 meters and for Railway Crossings around 14-19 meters to ensure adequate electrical clearances.
- However, MAHSR alignment will be on Viaduct with a height of 8- 12 meters from the ground level.
- For the construction of the viaduct, Girder Launching technique will be adopted.
- Due to these requirements, Transmission Lines crossing the MAHSR corridor are required to be raised at a height of more than 30 meters, which will be more than the normal height required in case of Railway Crossings/National Highways etc.
- To accommodate the height of the towers and sustain the weight due to increase in the height of the tower, broader foundation is required.
- Engineers from NHSRCL and GETCO after a lot of brainstorming, improvised the design of the towers to suit the MAHSR corridor’s requirements.
- Special Narrow Base Tower Design has been adopted for the shifting of Transmission Lines infringing with MAHSR Project.
- This unique Narrow Base Tower Design requires 80% less land for Tower Foundations (size 10.5 Mtrs X 10.5 Mtrs) in comparison to conventional towers (Size 23 Mtrs X 23 Mtrs), which can accommodate up to Four EHT lines (i.e. 12 Phases), and can be as high as 96 Mtrs.
- This is an ideal solution for Viaduct based Railways crossing & future expansions of transmission lines.
- The new improved design has also reduced the requirement of concrete to 1/3rd (from 780 Cum to 270 Cum, per tower) & steel reinforcement 1/6th (from 90 MT to 12 MT, per tower) of original without compromising the Safety & Strength of the Transmission Lines.
- This Narrow Base Tower Design will not only proved instrumental in saving land but also help in economizing the consumption of national resources (Steel & Concrete) without compromising the safe construction & operation of Transmission Lines.
Source: NHSRCL-Press Release