Aluminium Clad Steel Wires: Bringing ‘Resistance’ to the Power Supply Chain

Live-line installations of OPGW is the latest technology used by power distribution companies to combine the benefits of earthing while providing a comfortable route for internal and external communications. The role of OPGW and aluminium-clad steel wires in connecting cities and changing the face of telecommunications is clearly understood. Several companies are now focusing on laying the power infrastructure across the country using smart technology that serves a dual function.

OPGW explained
Optical Ground Wire Fibres (OPGW) are used by the power distribution industry to be placed at the highest position of the transmission line. This position is critical because it protects the conductors from lightning on one hand while it provides a telecommunication pathway for internal and external communications. This is the reason why it is called a dual-functioning cable because it plays the role of an earth wire on one hand while helping telecommunication on the other. The OPGW used should be sturdy enough to handle mechanical stresses caused by weather conditions like wind and ice. It should also have the capability to manage electrical faults by providing earthing without causing damage to the sensitive optical fibres inside the cable.

Need for Aluminium-Clad Steel wires
Aluminium-clad steel wires are often used as the armour wire of OPGW because it is a bimetallic wire with a steel core that is covered with aluminium. These specially made wires are resistant to corrosion which makes them ideal for use in industrial, semi-industrial and marine conditions. This is considered better than aluminized steel. It is 15% lighter but has the same tensile strength as extra high-strength steel. It offers better conductivity compared to galvanised steel and aluminium considered in isolation. This is the reason why aluminium-clad steel wire is preferred in OPGW, especially in coastal and island areas, areas with dense fog or areas with high pollution where the risk of corrosion is higher.

Power system operators impose restrictions on the planned outages of transmission lines. A solution to this is the usage of OPGW stringing with energised transmission lines using a safe method called carrier. This system involves the use of a self-propelled carrier that moves on the existing grounding wire while pulling an aramid rope and positioning several double pulleys. When the pulley strings the OPGW, it replaces the existing ground wire.

Benefits of Live Line Installation of OPGW
The need of the hour is to bring radical changes in power distribution by introducing smart energy management solutions that can reduce the burden on existing power infrastructures. OPGW is a game-changing solution that allows for synergies between power distribution grids and fast optical fibre-based Supervision Control and Data Acquisition networks offering power utility companies the dual capabilities of a telecom carrier. OPGW also manages the real-time monitoring of the transmission network over which it is installed, combining the activities of grounding and communications.

The OPGW within the cable can be utilised for the transmission of data at high speed for the internal security of the transmission line and internal data communication or leased out to other service providers for a high-speed connection between cities. Being an insulator it protects the transmission line from lightning, noise disturbance and cross-connections. The cable is designed compactly to decrease the impact of ice and wind. There is no need to alter the route or towers to replace the existing ground wire with OPGW. The cables are protected by a bundle of aluminium clad steel wires which are excellent conductors.

There is a cost advantage in using OPGW for communication over a buried optical fibre cable since the installation cost per kilometre is cheaper. It is a low cost solution for providing communication and data backbone trunks. There is no requirement for ownership of land to lay OPGW as power transmission companies already possess the right of way for their towers. Overhead OPGW cables run a lower risk of damage due to ground repair work for the underground drainage system or roads, animals etc. Moreover, activities like digging and filling trenches is not required as the cable is laid overhead not underground which makes execution faster especially in inhospitable terrain.

Laying out an OPGW network is quick and can be completed via live-line installation without the interruption of power flow. Power companies get the benefit of high return on investment as they can provide extremely high capacity links to telecom service providers in a secure manner. OPGWs have a lifespan of at least 40 years which makes this investment worthwhile.

Conclusion
In today’s fast paced world where quick communication is key, adoption of OPGW is imperative. They are very reliable provided they are installed correctly. Live line installations brings in the change that is needed to optimize the power distribution system and bring in the dual benefit of grounding and providing high-speed communication. Smart technology will help to lay such networks quicker, strengthening the power infrastructure across India and improving the telecommunication grid. Given the rapid evolution of the business landscape and the need for faster communication, it is imperative that OPGW technology is used for liveline installation on a widespread basis.

- Shalin Sheth, Founder, Managing Director, Advait Infratech Limited