Time for an upgrade

Why investing inreconductoring and uprating transmission lines is an investment in future, says

Shalin Sheth.



Founder, ManagingDirector,

Advait Infratech Limited.

Due to the growingnetwork capacities and requirements for high availability and bandwidth, power utilitiesare now concentrating on reconductoring and uprating transmission networks. Inthis light, India expects its yearly energy demand to rise by an average of 7.2per cent and the installation of 27,000 circuit kilometres of interstate powertransmission networks by 2024, according to a proposed plan by the government'spower ministry.

Parallel to this realityis the nation's aging transmission infrastructure, which is estimated toconsist of 192,000 circuit km of transmission lines with a voltage of 66 kV orhigher and is thought to be older than 30 years. Its outdated componentsrequire evaluation, reconductoring, and strengthening. This is wherereconductoring and uprating are believed to be crucial for the growth anddurability of the country's transmission infrastructure.

Voltage uprating can bedesirable when significant power increases are required, but other solutionscan be preferred when just a little rise is necessary.

In recent years, numeroustransmission utilities have started reconductoring projects to meet theincreased load demand, reduce transmission and distribution losses, and providea dependable power supply. Some of these include the JKPDD proposal for the upgrade of theWagoora-Zainakote transmission line in 2021, the first live line projectin Bengaluru in 2019, and MSETCL’s project in 2014 and Advait’s Goareconductoring project.

The Bengaluru project of2019 doubled its power transfer magnitude by uprating its current 66kVtransmission line, while the high power command used in the lines offeredbetter elevation from the ground and neighbouring structures.

Reconductoringand Uprating: Future investments


Uprating a linenecessitates a design change that minimizes losses and raises the voltage ofthe line to the next acceptable voltage level without bringing the line nearits temperature limit. However, voltage uprating requires larger cables, biggertransformers, and other modifications, which need new conductor installationand the construction of new towers or modifications to existing towers.

The only benefit ofreconstructing the line in this fashion is that it lessens the upgrade'sinfluence on the transmission line’s footprint and might simplify planning andpermitting while cutting expenses.

Line arresters can makeuprating existing transmission lines and substations to higher voltages morefeasible. At a substation, using line arresters allows for lower clearanceswhile maintaining correct electrical clearances and allowing for the additionof new equipment.

Uprating has considerablefinancial advantages because its associated expenses are far lower thanrebuilding the entire substation. The use of line arresters can be especiallyadvantageous in areas with high land costs.

Less clearance duringsystem upgrades can also result in lower bus heights, which, if necessary, canresult in lower expenditures for aesthetic treatments like walls and otherobstacles. Modern conductors with greater strength-to-weight ratios, largerworking temperature limits, and better high-temperature sag performance canhelp unlock untapped uprating potential. However, if uprating does not producethe required results, reconductoring is advised.


Reconductoring entailsswapping-out outdated conductors for more modern ones, such as hybrid coreconductors made of aluminium and steel supplemented by high-temperature low-sagconductors, high-temperature superconductors, etc. These conductors have lowheat generation and low technical losses, allowing them to handle largercurrents and temperatures easily.

Using conductors madefrom special alloys can withstand temperatures of up to 210°C. These conductorshave a temperature range of 80°C to 90°C and may transmit more electric currentthan ordinary conductors.

The new materials avoidsag and conductor pull, preventing tower adaptations and replacements withhigher towers. For new lines, HTLS conductors can be utilized, and because theyare frequently ‘tailor-made’ for a project, each project must be looked intoindividually.

The thermal rating of theline can be significantly increased by substituting a conventional conductorwith an HTLS conductor, which makes use of the current transmission towers andROWs. Long spans across rivers that are particularly susceptible to sag are oneapplication where these conductors are useful. Without the need for new lines,they can also increase the grid's dependability.

By holding back the extracapacity made possible by the HTLS cable’s ability to carry high currents,other lines in the vicinity can expand their capacity and the HTLS cable cansupport the extra load if one of those other lines fails while the down line isbeing fixed. By increasing the voltage of the line, line capacity can also beboosted by more than 100 per cent without affecting the current flow during thereconductoring operation.

In some situations, itcan allow for a minimal increase in system voltage — between 40 and 60 kV withlittle to no need for physical modification or reliability. For a greatervoltage improvement, the transmission line and transformer designs need toundergo more substantial physical alterations.

The savings from usingthe old ROW and towers, together with the decreased or eliminated permittingexpenses, make up for the additional cost of installing HTLS conductors. Thefact that it enables utilities to prolong the life of aging transmission linesand speeds up the decarbonisation of the electrical grid are other importantelements encouraging the development in reconductoring of lines.


Although the executionhas some difficulties, reconductoring and uprating offer a lot of potential. Theyare essential to strengthening the transmission network since they cansuccessfully increase the capacity of the current transmission lines andcorridors. Reconductorizing the vast majority of out-of-date infrastructurealready in use is the ideal place to start because it will create a wealth ofoptions for the sector to effectively utilise the capacity of the current grid.

Voltage uprating can bedesirable when significant power increases are required, but other solutionscan be preferred when just a little rise is necessary.

Using conductors madefrom special alloys can withstand temperatures of up to 210°C. These conductorshave a temperature range of 80°C to 90°C and may transmit more electric currentthan ordinary conductors.

One of a kind!

Pool Yard House, designed for an elderly couple and their visiting family and friends by Ar. Badrinath Kaleru and his team is a one-of-its-kind house that exudes comfort.

Project Name: Pool Yard House.
Location: Sec–7, Panchkula, Haryana, India.
Built up area: 496 Sq. Mt.
Completed in: 2017.
Principal  
Framework for the future

The GMS Grande Palladium project in Mumbai is a critical commentary on some of the antiquated notions that have plagued contemporary commercial design in the subcontinent.

Rapid urbanization and redevelopment has led to a blanket erasure of any identifiable architectural character in Mumbai, barring a few. The site for the GMS Grande Palladium is in close proximity t   READ MORE...
Garden of Paradise

The villa project in Bengaluru has been developed by KGA around an exceptionally well-planned central landscape, resulting in natural light and ventilation, yet privacy for each owner from neighbours. 

Architects: Karan Grover & Associates.
Category: Residential Villas.
Project Title: Raffles Par