Sanjay Bhagat | Vice President & Head - TLT BU, Bajaj Electrical Ltd
When was monopoles introduced for T&D use in India and what is its current size, and what is the lag with which it was introduced here in India when compared to the US and Europe?
Developed power sector markets like North America and Europe have been using monopoles since 1960s. However BEL had set-up the first world-class, state-of-the-art galvanized steel structure manufacturing unit in India at MIDC Ranjangaon, near Pune in 2002. Thereafter, BEL designed and successfully commissioned first 400-kV DC monopole for transmission application in India in 2007.
In India, market for T&D monopoles is still at a very nascent stage. However, there are plenty of opportunities for growth, considering severe right of way (RoW) related constraints and increasing need for better aesthetics especially in upcoming smart cities.
Following are the major advantages:
1.Shorter project delivery period
2.Minimum space requirement
3.Faster & safer mechanised tower erection
4.Smaller footprint and hence lesser environment impact
5.Protection against vandalism
6.Aesthetically pleasing designs
7.Better inventory management as lesser components need to be handled
Disadvantages are as follows:
1.Higher weight and cost as compared to angular lattice tower
2.Difficulty in transportation & installation especially in hilly areas
3.Manufacturing limitations for voltage range of 765 kV and above.
What are the differences in carrying capacities between monopoles and lattice towers and the frequency levels in a transmission line? Can they be adapted to both AC and DC lines?
There are no differences in carrying capacities or the frequency levels in monopole and angular tower. Monopole can be designed and adapted for both AC and DC transmission and distribution applications. However there are limitations in manufacturing of transmission monopoles of voltage range of 765 kV and above.
What are the obstacles in spreading the use of monopoles in the current scenario and what are the measures required to speed-up their adoption on a wider scale?
At present, major obstacle is lack of awareness about monopoles and expertise with Indian utilities. As the market for monopoles has not yet fully evolved, there is no standardisation of specifications, designs or installation methodologies. With more monopole projects coming up in recent years, we can expect better standardisation in the years to come.
Present prices of monopoles are much higher than that of angular lattice structures mainly due to smaller market size and non-standardisation. With increase in market size, better availability of raw materials and manufacturing optimisation, prices of monopoles will surely get reduced, making it more attractive.
What is the possibility and need for replacing the existing T&D tower infrastructure with monopoles in the years to come?
As monopoles occupy lesser space, existing transmission lines can be upgraded to higher voltage class by using the existing corridor. Monopoles can replace lattice towers in urban/ semi-urban areas for want of space optimisation and better aesthetics. Monopole structures are a good option for entry and exit points of transmission lines at the existing substations in urban/ semi-urban areas where cost of land is very high. Monopoles can also be a better option for providing T&D network in upcoming smart cities in India.
Are there any global standards evolved for monopoles? What is the status of R&D in monopoles in India?
Global Standard for Design of Monopole is ASCE 48-11 (American Society of Civil Engineers). In India, CBIP has recently introduced Monopoles in Transmission Line Manual - 323.
Slowly but steadily, Indian utilities are demanding solutions to the constraints with newer and creative designs of monopoles as well as its civil foundations. BEL has in-house infrastructure to take up this challenge and provide customised concept to commissioning solutions which optimise space requirement and cost of monopole based T&D lines.
What are the categories of monopoles you make for the power sector, any joint venture partner you are associated with and who are your major clients in the power sector?
Bajaj Electricals Ltd. (BEL) manufactures a wide range of galvanized steel monopoles, right from 11 KV to 400 KV, for transmission and distribution (T&D) applications in the power sector. We have in-house set-up providing complete turnkey services from concept to commissioning. There are no joint venture partners in this area of operations.
BEL has the pioneer of monopoles in India. We executed India´s first monopole project, almost a decade ago, comprising of a 400-kV double circuit transmission line for Power Grid Corporation of India Ltd (PGCIL). Our major clients are the Central/ state utilities and a few private customers who are looking for transmission line diversions due to space constraints.