Over the years, Power Grid Corporation of India Limited (Powergrid) has positioned itself as a key player in the telecom domain. Powergrid is India’s largest electric power transmission utility, exercising control over 169,313 ckm of transmission lines operational at 800/ 765kV, 400kV, 220kV and 132kV EHVAC, and +500kV HVDC capacity levels. Further, the company has 252 power substations. As far as Powergrid’s network strength is concerned, the government-owned utility is present in all telecom circles, with a total telecom network spanning 67,000 km and more than 99.5 per cent network availability. Powergrid’s network connects over 1,000 locations across the country that carry traffic in multiples of 10G/100G, in rings. In addition, Powergrid currently has a unified licence for providing national long distance services and internet services. One of the key strengths of Powergrid is its optic ground wire (OPGW) network, which spans over 80,000 km.
Advantages of OPGW fibre
OPGW is suitable for power transmission lines above 132 kV. All dielectric self-supporting and wraparound cables can be used below the 132 kV level. Further, OPGW can act as earth wire as well as OFC. Another key benefit of such a set-up is that it ensures very high availability for telecom networks.
Moreover, the roll-out process for an OPGW network is much faster and mostly entails live line installation without disruption of power flow. Given these benefits, Powergrid’s network is very advantageous in tough terrain areas such as Jammu and Kashmir, Ladakh and other north-eastern states.
Another key feature of Powergrid’s OPGW fibre is that it runs on extra high voltage transmission lines, and fibre connectivity may also be provided for base transceiver stations (BTSs).
Furthermore, customers appreciate that OPGW has more inherent redundancy than underground fibre optic cable (UGOFC). Since OPGW does not intrude on the RoW of highways, it is truly path redundant. As per Powergrid, another key benefit of the OPGW network is that all equipment is located at secure locations, such as its own power substations, which have assured power supply. However, the protection paths are sometimes longer.
Use of transmission line towers for installation of mobile antenna
In addition to offering a wide OPGW network, Powergrid is offering tower space on its transmission line towers for installation of telecom antenna. At present, Powergrid has 250,000 transmission towers across the country, with each tower being about 40-50 metres tall.
These towers have reliable power supply standing at over 99.5 per cent, which helps to keep the BTSs and other telecom equipment mounted on them functional. The company has deployed unique solution to draw the power from isolated earth wires of power lines.
Further, as per Powergrid, platforms have been created on tower legs for installation of telecom and power equipment such as potential transformers, lightning arresters, battery banks and BTSs. These platforms are constructed at a height of 7-8 metres and are therefore safe from floods and other such calamities.
Challenges in the way
While the benefits of OPGW networks are plenty, the challenges in the way of laying OPGW fibre are no less. At present, OPGW networks are available only up to the periphery of cities. When operators try to extend this to intra-city networks, challenges such as maintaining the reliability of the OPGW, availability of utility grade fibre, and obtaining RoW permissions come in the way.
Industry leaders have also said that specialised skill sets and manpower are required to address the operation and maintenance needs of OPGW networks.
Going forward, the company is planning to expand its OPGW network by an additional 50,000 km. Powergrid plans to do this by both utilising existing transmission lines and laying OPGW fibre across new power transmission lines. In addition, the power utility is aiming to increase its installed capacity from 17 Tbps to 25 Tbps. The ultimate goal is to be able to lease out its UGOFC and OPGW/UG utility fibre to create an intra-city network.
Over and above this, the company is set to venture into complementary business segments such as international long distance, data centres and fiberised telecom towers with power supply.