We need more power corridors in the country

Dhavaleshwar Puvatti, Product Manager (Product Engineering), Fluentgrid Ltd in an interview with EPR Magazine

Regarding transmission line capacity challenges, Dhavaleshwar Puvatti, Product Manager (Product Engineering), Fluentgrid Ltd., says, “ When we look at grid functioning, we still face a flip situation of not being able to provide adequate power corridors at many load centres, including capitals.” The government plans to add about 17,500 Ckm of transmission lines annually and 80,000 MVA of transmission capacity yearly in India. 

What kind of opportunities will this create? 

The Indian grid still experiences congestionbased power evacuation and scheduling curtailments throughout the year at some or many flow corridors. Historically, transmission lines and infrastructure were created in response to specific needs. The utility would choose a generating station and request an evacuation corridor from CTU/ STU to ferry this power to its consumers. In many cases, the network development happened in a “patchwork” fashion, which only served a limited timeline need. This plan of network addition will pave the way for national-level high-capacity corridors, which will ambitiously serve the current and expected increase in power demand. The opportunities are numerous, ranging from the development of industrial corridors and SEZs to the creation of energy adequacy, the support of pan-India grid-EV programs, and ambitious renewable initiatives, all of which create lakhs of direct and indirect job opportunities. However, the plan should be very inclusive and strategy-oriented. Rather than entirely new networks, existing lines should also be upgraded. 

What measures do we need to take to ensure efficiency and optimal performance in transmission lines?

 Firstly, unlocking more capacity inside existing transmission lines provides significant system efficiency and reliability benefits. Current carrying capacity is traditionally adjusted to seasonally fluctuating values based on an estimate of environmental and operational loading circumstances. Because these circumstances persist only for brief periods, this technique will frequently come under or overload existing transmission systems. The primary variables with the current technology available that would assure efficiency and optimal performance in transmission lines are: • Robust and maintenance-friendly design considerations. • The use of HTLS conductors. • High-strength polymer insulators.

 What are the transmission congestion challenges of urbanisation and fast growth in cities?

The main challenge is very poised; where we have an installed generation capacity of more than 400GW and are nerved throughout the country by > 460000 km of transmission lines at 200kV level and above; yet when we look at grid functioning, we still face a flip situation of not being able to provide adequate power corridors at many load centres, including capitals; and, ironically, there will also be the huge installed capacity of the transmission network and the substations. This congestion is not only affecting energy requirements but also causing various strategic ripples in the economy.

What are your thoughts on the burdens faced by urban utilities today? 

Firstly, most urban utilities have owed hundreds to thousands of crores to other state agencies for the electricity consumed. Another predominant issue is the availability of good import capability at the transmission level, and sub-transmission/primary distribution links to supply imported power. Although the metering to collection efficiency is quite good in urban areas, the expenditure incurred in setting up the underground distribution network and O&M expenses is on the higher side. Electrical network health, pilferage, and revenue realisation aspects also burden utilities and force them to resort to variations on aspects of service delivery across the zones, as reflected by more power cuts, unscheduled power cuts, difficulty in getting a connection, and lack of immediate response in certain localities of the same utility area. The burdens are more heterogeneous. However, the advent of IT/OT applications, grid visibility, and consumer services is unburdening urban utilities. 

What are the upcoming technology trends in overhead transmission wires and underground cables? 

In overhead transmission, the High-temperature LowSag (HTLS) conductors are promising. They offer 30–40 per cent more capacity by withstanding higher operating temperatures, thus carrying a higher amount of power than conventional ACSR conductors and correspondingly having a lower slag, reducing the number of towers needed. As it relates to underground cables, gas insulated lines (GIL) are another alternative for high-capacity power transfer that is picking up share rapidly. Recently, insulation gas was shifted from 100 per cent SF6 gas to a composite gas mixture of 80 per cent N2 and 20 per cent SF6, reducing cost and increasing the long-term withstand strength of GIL tubes against internal arcs.